Answer:
The molecular clock has limited usefulness for estimating divergence times among species in part due to the saturation of DNA sequences. This occurs because In highly diverged lineages, the substitutions process will occur at sites that have been substituted previously.
Explanation:
The mutation rate is used by the molecular clock to shorten the ancient period during which living forms separated. Both amino acid sequences plus DNA's nucleotide sequences are used by the molecular clock.
Only the percentage of mutations as well as other modifications over a predetermined period of time are recorded by this clock. Frequently, a property's usefulness may be restricted by the lineages' extreme diversity. The researchers come to the conclusion that molecular clocks are significantly so "erratic" comparatively previously believed, making them essentially worthless for maintaining precise evolutionary time. They blame natural selection's biases, which can occasionally prevent particular genetic mutations in particular lineages.
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Experiments involving the cloning of toxin molecules with ld50 < 100 ng/kg fall under which category of experiments?
Experiments involving the cloning of toxin molecules with LD50 < 100 ng/kg fall under the category of experiments that require NIH OSP and IBC approval before initiation.
In LD50, the LD stands for Lethal Dose. It determines the amount of chemical/toxin required to kill the 50 % organisms of the total population. This is used to measure the acute toxicity of any material. The unit for measure of DD50 is milligrams of chemical per kilogram of body weight.
NIH is the National Institute of Health. It is inclined towards the research upon medical and behavioral aspects. The aim of conducting such researches is to reduce the diseases and increase wellness in the society.
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. About how long ago did Archimedes live?
A. 2,260 years ago
B. 2,000 years ago
C. 250 years ago
D. 2,000,000 years ago
The location where infectious organisms can multiply and accumulate is referred to as the _____
The location where infectious organisms can multiply and accumulate is referred to as the reservoir.
Infectious organisms are those that cause disease in other species They are also called pathogens. They can be bacteria, virus, protozoans, etc. The organism can cause disease either by living inside the body or even by living outside the body.
Reservoir is simple words is the habitat of an infectious organism. This can be humans, animals and also plants. On the basis of their locations, reservoirs are of three types: human, animal (non-human), and environmental. The infectious organisms from environmental reservoirs can be transmitted to the host by several modes of transmission.
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True or False:
Repetition Practice interferes with the ability to learn new information
Repetition Practice interferes with the ability to learn new information is true.
It is impossible to overstate the value of repetition. In fact, it needs to be emphasized again how important repetition is as a learning tool. It enables the transfer of a conscious skill into the subconscious, freeing up working memory and enabling the acquisition of new skills. Repetition gives kids the practice they need to acquire new skills, so it's a good thing. Repetition helps kids learn faster, builds confidence, and fortifies the neural connections in their brains that support learning. Practice doesn't always make perfect while learning a new skill. Zachariah Reagh and Michael Yassa, neurobiologists at UC Irvine, discovered that while repetition improves the factual content of memories, it can decrease the amount of detail associated with such memories.
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What are the five regions of the vertebral column? describe one differentiating feature of the vertebrae in each region.
The five regions of the vertebral column are cervical, thoracic, lumbar, sacral, and coccygeal (or caudal) regions. One differentiating feature of these vertebrae includes their primary functions.
The vertebral column is the central axis of all vertebrates. It protects the spinal cord, provides attachment to the muscle cells, and supports the trunk. It usually consists of 33 vertebrae. The vertebral column in mammals is composed of five different groups of vertebrae:
Cervical region
The primary function is to support the weight of the head. They are numbered C1 to C7. C1 and C2 allow movement of the head.
Thoracic region
The primary function is to hold the rib cage in its place and protect the heart and lungs. They are numbered T1 to T12. They allow limited movement only.
Lumbar region
The primary function is to hold the weight of the body. They have numbered L1 to L5. They allow holding heaving weight.
Sacral region
The main function is to connect the spine to the hip bones (iliac). The five sacral bones are fused and form the pelvic girdle along with the iliac bones.
Coccygeal region
The four coccyx bones provide support to the attachment of ligaments and muscles of the pelvic region.
With the support of the above answer, we can say that there are five regions in a vertebral column, namely, cervical, thoracic, lumbar, sacral, and coccygeal.
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When using a wet mount on a brightfield microscope, what could you add to your specimen?
In a wet mount, the specimen is held in place between the slide and cover slip by a drop of water. On the slide, place a sample. Put a drop of water on the sample with a pipette. Place the cover slip's edge over the sample and slowly drop it into position using a toothpick or something similar.
What kind of solution should be prepared a moist mount?Wet mounts may be created using a variety of substances. You may use water, immersion oil, and glycerin (glycerol), with water likely being the most popular.
In a wet mount, a little drop of water is applied to the slide, and the specimen is covered with a cover slip to preserve it.
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The molecules activated by light in photoreceptors are called:_______
a. the sclera
b. the na/ca exchanger
c. rhodopsin
d. the voltage gated sodium channels
e. guanylyl cyclase
The molecules activated by light in photoreceptors are called rhodopsin
Photoreceptors are the cells in the retina that are specialized to respond to the light ans are called visual photo-transduction. They function is to convert the light into stimuli which can be processed by our brain.
They absorb the photons and causes a change in the cell membrane potential. They are of three types- rodes, cones and intrinsically photosensitive retinol ganglion cells.
Rods are more sensitive and are used in low light vision while cons are used in bright light vision.
Rods contain a photosensitive pigment called rhodopsin which is extremely sensitive to light. it is activated by even dim light.
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The basic structure of the plasma membrane is a diverse collection of proteins floating within a lipid framework, which is often referred to as the ______.
Fluid mosaic model
The basic structure of the plasma membrane is a diverse collection of proteins floating within a lipid framework, which is often referred to as the fluid mosaic model.
Describe the fluid mosaic model.Phospholipids, cholesterol, and proteins are only a handful of the substances that are constantly flowing through the cell membrane, according to the fluid mosaic theory. This movement helps the cell membrane preserve its function as a partition separating the cell's internal and external surroundings.What are the fluid mosaic model's primary components?The creators of the fluid mosaic model are S.J. Singer and Garth L. Nicolson. According to this hypothesis, the plasma membrane of animal cells is made up of a patchwork of substances, including phospholipids, proteins, cholesterol, and carbohydrates. The fluidity of the membranes is due to these components.What makes the fluid mosaic model mosaic?Due to the following characteristics of cell membranes, which are depicted using a fluid-mosaic model:
The phospholipid bilayer is fluid; each phospholipid can move around in its place.When proteins are implanted in the phospholipid bilayer, a mosaic of components is produced.To learn more about fluid mosaic model visit:
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The observable expression of one's genetic makeup is referred to as his or her _________.
During which event of hemostasis do clotting factors (procoagulants) assist with the transformation of blood from a liquid to a gel?
coagulation stage
During coagulation stage of hemostasis do clotting factors (procoagulants) assist with the transformation of blood from a liquid to a gel.
Blood clots are created when blood coagulates, or turns from a liquid to a gel. Hemostasis, the halting of blood loss from a damaged vessel, may ensue, followed by repair.Platelets are directed to the location of the damage, while normal blood flow is kept in the uninjured parts, limiting coagulation to the affected tissue.Platelet activation, adhesion, and aggregation as well as fibrin deposition and maturation are all components of the coagulation mechanism.What are the two fundamental steps in the coagulation of blood?The intrinsic and extrinsic routes, which are two distinct but interconnected pathways, play a role in the clotting cascade. External trauma that causes blood to escape from the vascular system activates the extrinsic route. Compared to the intrinsic pathway, this pathway is faster.To learn more about coagulation visit:
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Persons with __________ blood have neither antigen a nor antigen b on their red blood cells but have antibody anti-a and antibody anti-b in their plasma.
Persons with O blood have neither antigen a nor antigen b on their red blood cells but have antibody anti-a and antibody anti-b in their plasma.
ABO blood grouping was discovered by Austrian scientist Landsteiner. It consist of four blood groups- A, B, AB, & O.
Red blood cells have certain extension of the proteins that are called antigen. Two types of antigens are there antigen a & b. The RBCs which have a particular antigen will not have the antibody against the same.
Blood Group A has antigen A and antibody B. Blood group B has antigen B and antibody A. Blood group AB has both antigen and no antibodies while blood group O has no antigen and antibody A & B.
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What is a period in the periodic table?
The vertical column of elements
Each element
The horizontal row of elements
The particles of similar atoms
A period in the periodic table is the horizontal row of elements (option C).
What is a periodic table?The periodic table is a tabular chart of the chemical elements according to their atomic numbers so that elements with similar properties are in the same group (column).
The periodic table arranges chemical elements into groups and periods. The vertical column is called the groups while the horizontal rows are called the periods.
In the periodic table, there are 7 periods and 18 groups that encompass the chemical elements.
Therefore, a period in the periodic table is the horizontal row of elements.
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Different chemical elements will create a different scattering of absorption lines in the spectrum of visible light. We understand the interaction of an atom with light, and because of this we can predict where the lines should be and verify this in a lab. This process is called?
A. Astronomy
b.Nucleosynthesis
c.Spectroscopy
d. Star formation
Chemists research the interactions of many types of electromagnetic radiation with atoms and molecules. The term "spectroscopy" refers to this interaction.
Because various elements have varying quantities of protons and varied numbers and configurations of electrons, they also have different spectra. The variations in spectra are a result of the energy that atoms absorb or emit as their electrons shift between different energy levels. A transition from ground state or lower-energy excited state to a greater excited state can occur as a result of an atom's ability to absorb light of a certain energy. As a result, an element's emission spectrum is converted into an absorption spectrum, which contains dark lines aligned with brilliant lines. Chemists research the interactions of many types of electromagnetic radiation with atoms and molecules. The term "spectroscopy" refers to this interaction. Ordinary stars like the Sun have absorption lines in their spectra because some of the continuous light emanating from the hot, dense interior is absorbed by the fragile outer layers of the stellar atmosphere, known as the photosphere.Learn more about spectroscopy here:
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______ are carbohydrates that are not well digested by human enzymes, but they can be fermented by beneficial bacteria in the large intestine.
Prebiotics are carbohydrates that are not well digested by human enzymes, but they can be fermented by beneficial bacteria in the large intestine.
Prebiotics- Foods include whole grains, bananas, onions, garlic, and artichokes contain prebiotics. Additionally, probiotics and prebiotics can be found as dietary supplements and are added to select meals. The connection between the gut microbiota and illness is still being studied.
Fermentation- An anaerobic process called fermentation allows glucose to release energy even in the absence of oxygen. In addition to yeast cells, bacteria and animal muscle cells also undergo some sort of fermentation. For instance, yeast uses fermentation to create alcohol from sugar in order to get energy.
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A(n) ____________________ is a sequence of organic nitrogen base pairs that codes for a polypeptide or a protein.
A(n) gene is a sequence of organic nitrogen base pairs that codes for a polypeptide or a protein.
What is polypeptide?
Peptides are made up of short chains of amino acids joined together by peptide bonds. The word "peptide" comes from the Ancient Greek word "peptós," which means "digested." Oligopeptides, which comprise dipeptides, tripeptides, and tetrapeptides, are chains of fewer than twenty amino acids.
A polypeptide is a peptide chain that is longer, continuous, and unbranched.
Therefore, along with nucleic acids, oligosaccharides, polysaccharides, and others, peptides belong to the large chemical families of biological polymers and oligomers.
A protein is a polypeptide that has more than 50 amino acids, on average. A protein is made up of one or more polypeptides that are structured in a biologically useful manner. Proteins are frequently coupled to other proteins, other macromolecules like DNA or RNA, or complex macromolecular assemblies.
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a) The carbohydrates cellulose and starch are functionally different due to the ____?
A. Reaction used to join their monosaccharides.
B. Specific monosaccharides used to build them.
C. Arrangement of their monosaccharides.
D. Functional groups contained within their monosaccharides.
b) Why is that the answer?
a) The answer is C. Arrangement of their monosaccharides.
b) The reason for this answer is : The main distinction between starch and cellulose is that starch is a storage polysaccharide with alpha 1,4 links between glucose monomers, whereas cellulose is a structural polysaccharide with beta 1,4 connections between glucose monomers. The primary distinction is that while plants employ cellulose to construct structure, they use starch to store energy. In contrast to cellulose, where each succeeding glucose unit is rotated 180 degrees, starch repeat units are situated in the same direction. Compared to sugar, which is not water soluble, cellulose is thicker. On the other hand, starch may be dissolved in warm water and is less brittle than cellulose. Since mammals absorb starch, cellulose is not suitable for human diet.
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A nerve impulse moves toward a neuron's cell body along _____. a nerve impulse moves toward a neuron's cell body along _____. dendrites synaptic terminals oligodendrocytes axons nodes of ranvier
A nerve impulse moves toward a neuron's cell body along dendrites.
A nerve impulse is an electrical charge that is generated as a result of any stimuli that travel along the neuron membrane and is also called an action potential.
The nervous system consists of neurons which are also known as nerve cells that receive sensory signals from the external environment and integrate the input signals and then relay these signals to the target cells and organs. Sensory, motor, and interneurons are the three main types of neurons present in human beings.
Neurons are made up of three main parts which are dendrites, axons, and cell body. The cell body is also called soma.
Dendrites are the receiving part of the neuron and carry the impulses to the cell body by receiving inputs from the axon.
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An example of _________ correlation would be the more a mother smokes, the more damage a fetus suffers.
Positive
An example of positive correlation would be the more a mother smokes, the more damage a fetus suffers.
What is a positive correlation?A positive correlation is defined as the tendency of two variables to move in the same direction.When one variable tends to go down as the other goes down or when one variable tends to go up as the other goes up, there is a positive correlation.How can you tell if a correlation is favorable?The correlation coefficient is calculated on a scale from + 1 to -1.Either + 1 or -1 represents a variable's complete connection with another. When one variable declines as the other grows, the correlation is negative; when both variables increase , it is positive.To learn more about correlation visit:
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A hypothesis may be considered what?
Answer:
a tentative, testable explanation
Explanation:
Answer:
A hypothesis is a testable assumption/prediction that you make based on some basic evidence. It is the starting point for further investigation.
Explanation:
:D
6. bears were once present as far south as california. over time they have disappeared
in most of the lower 48 states. how might the influx of humans have influenced bear
populations?
Bears were once present as far south as California. Over time they have disappeared in most of the lower 48 states.
Human have influenced bear populations as they are a factor of resource competition for the bear species, due to the fact that the resource available in the environment have value to both humans and bears. Major changes in disturbance cycles and landscape mosaics brought by humans have further affected temporal and spatial pulses of bear food production. Air pollution has also affected bear food biomass on a small scale and is likely to have major future impacts on bear habitat climatic warming.
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How much rotation of the body is required for the posterior axial oblique projection for acetablulm?
The posterior oblique (Judet method) for the acetabulum requires a 10- to 15-degree rotation of the body.
What is acetablulm ?The acetabulum is the hip joint's socket. Types of acetabular fractures are categorised based on pattern and severity. Acetabular fractures are distressing wounds that typically call for surgery. The cartilage that encircles your hip socket might cause complications like hip arthritis.
The three bones that make up our hip are together to form the acetabulum, which resembles a cup. The hip joint is created when the femoral head of the femur bone fits into this socket. We can walk, run, and move about freely thanks to these two anatomy components working together.Learn more about Acetabulum here:
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A nurse is explaining to another nurse the difference between first-generation antipsychotics and second-generation antipsychotics. what is the biggest benefit of the second-generation antipsychotics?
A nurse is explaining to another nurse the difference between first-generation antipsychotics and second-generation antipsychotics. what is the biggest benefit of the second-generation antipsychotics?
First generation antipsyhotics are the conventional antipsyhotics which blocks the dopamine pathway by blocking the D2 receptors and reduces the dopaminergic neuro-transmission.
Second generation antipsyhotics also called atypical antipsychotics which partial block dopamine receptors and also affect other things like serotonin.
Second generation antipsyhotics are more effective in reducing the symptoms schizophrenia and also improves the overall quality of life. They also have a lower risk of neurological symptoms like tremors, like the first generation drugs.
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ASAP Please Help
The rate of photosynthesis can be measured as the volume of oxygen released by a
plant per minute. The number of bubbles of gas released per minute from waterweed is
counted.
a. The gas collected in this experiment is not pure oxygen. Suggest a reason for this.
Answer:
The gas will be released.
Explanation:
In this experiment the solution used is sodium bicarbonate to increase the CO2 content for photosynthesis process.
So the gas released will not be only pure oxygen but also CO2 which is provided by the sodium bicarbonate solution.
list precautions used in the science laboratory to minimize the following risks
a) poisoning
b) scalding
c) eye damage
Answer:
Avoid skin and eye contact with all chemicals.
Minimize all chemical exposures.
Know locations of laboratory safety showers, eyewash stations, and fire extinguishers.
Assume that all chemicals of unknown toxicity are highly toxic.
Explanation:
In a diploid organism with 12 chromosomes, how many different arrangements of chromosomes can be generated by independent assortment?
Answer:
In a diploid organism with 12 chromosomes, 64 different arrangements of chromosomes can be generated by independent assortment
Explanation:
According to Mendel's independent assortment law, all of the alleles of two or more distinct genes are separately selected into gametes. We can also that an allele once per gene doesn't really affect the allele for just another gene that a gamete gets. This is an important step in sexual reproduction that enables 2 gamete cells to unite to form a diploid zygote that has all the DNA needed to develop a new life. Mendelian dihybrid crosses are an ideal demonstration of independent assortment. Spherical green, as well as wrinkled yellow, are two main pairings that indicate the genes responsible for seed color and shape are separately sorted. a member of a chromosome pair that share genetic information but comes from both sperm and eggs rather than another source.
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The nipple is located near the tip of each breast at about the level of the ______ and it is surrounded by a circular area of pigmented skin called ______.
The nipple is about the level of the lobe and it is surrounded by a circular region of pigmented skin called areola.
Both female and male sexual anatomy include breasts. Breasts are both functional for lactation and sexual organs in females (bringing pleasure). Male breasts serve no purpose. The nipples and areolae are among the breast anatomy that may be seen. The nipple, areola, nerves, mammary gland, and other structures are among the many parts of the breast.
In females, milk exits the breast through the lactiferous ducts from the nipple, a raised area of tissue on the breast's surface, to feed an infant. Milk may passively flow through the nipple or may be expelled by the ductal system's smooth muscle contractions. The areola, which frequently has a darker hue than the surrounding skin, surrounds the nipple.
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The transport of sugars into cells up their concentration gradient along with sodium ions that are moving down their concentration gradient is called ______.
The transport of sugars into cells up their concentration gradient along with sodium ions that are moving down their concentration gradient is called coupled transport or secondary active transport.
What is Active transport?Active transport may be defined as a type of transport that occurs against the concentration gradient. This transport is mediated by carrier proteins. Metabolic energy is used to move ions or molecules against a concentration gradient.
Primary active transport directly obtains energy from ATP, whereas secondary active transport obtains energy from the movement of an ion down its concentration gradient.
In this case, sodium moving down its concentration gradient fuels glucose moving against its gradient, so this is secondary active transport.
Therefore, coupled transport or secondary active transport allows the transport of sugars into cells up their concentration gradient along with sodium ions that are moving down their concentration gradient.
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Which subfield of biological anthropology is primarily concerned with the study of disease and trauma in archaeologically derived skeletal populations?
Paleopathology is the subfield of biological anthropology that is concerned with the study of disease and trauma in archaeologically derived skeletal populations
The study of people from the perspective of human biology, including the structure and functions of the human body, the environment, social behavior, and how these features have changed over time, is known as biological anthropology or physical anthropology.
The study of disease, both human and nonhuman, in antiquity utilizing a variety of sources, such as human mummified and skeletal remains, ancient texts, images from early books, paintings and sculpture from the past, and coprolites analyses, is known as paleopathology.
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Which organelle is involved in the destruction of bacteria, old organelles, and the liberation of enzymes?
An animal cell's organelle recycling facility, the lysosome is an organelle that houses digestive enzymes. It disassembles dated and pointless structures so that their molecules can be recycled. Some vesicles that exit the Golgi are directed to lysosomes, which are a component of the endomembrane system.
What are Enzymes ?Proteins called enzymes aid in accelerating our bodies' chemical reactions, or metabolism. Some compounds are created, while others are broken down. Enzymes are a part of all living things. Enzymes are created by our bodies spontaneously. However, food and manufactured goods both contain enzymes.
Based on the type of process they are employed to catalyse, enzymes are categorised into six functional classes. Hydrolases, oxidoreductases, lyases, transferases, ligases, and isomerases are the six different categories of enzymes.Learn more about Enzyme here:
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What possible uses do computerized devices have in optometry?
Coputerized devices are used to detect glaucoma, precise the cataract procedure and check for retinal tears.
What are the tools used by optometrists?Regular people may find the tools used by optometrists daunting, which is why many avoid or persistently put off getting their yearly eye exams. However, these tools are quick, effective, and incredibly accurate at determining the condition of the eye.
The common instruments used by ophthalmologists and optometrists to perform eye exams are listed below.
TonometerPhoropterRetinoscopeAutorefractorSnellen ChartRetinal CameraOphthalmoscopeVT 1 Vision ScreenerLearn more about the optometry with the help of the given link:
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