Answer:
axon; dendrite
Explanation:
A neuron has three main parts. These are axons, dendrites, and a cell body. Synapse is the site of communication between two neurons. The first neuron of a synapse is called the presynaptic neuron (sending neuron) while the second one is called the postsynaptic neuron (receiving). The axon of the presynaptic neuron and the dendrites of the postsynaptic neuron communicate with each other at the synapse as the axon of the first neuron delivers the nerve impulse away from the cell body.
Dendrites function as the receiving or input portions of a neuron. The plasma membranes of dendrites have numerous receptor sites for binding chemical messengers from the presynaptic neuron.
Answer: All of these
Explanation:
The polymerase chain reaction (PCR) revolutionized the field of molecular biology because PCR uses a small amount of DNA as a template.Paired with two primers which side to the target sequence, nucleotides, and thermostable DNA polymerase amplifies a specific region of DNA. In this way a large amount of DNA is obtained from a very small sample.
Answer:
3. An even number of chromosomes are required for synapsis during prophase I and proper pairing during metaphase
Explanation:
Mules are hybrids of a cross between a female horse and a male donkey. Horses contain 64 chromosomes while donkeys contain 63 chromosomes in their somatic cells respectively. This means that they each produce 32 and 31 chromosomes respectively during meiosis. A mule, hence, contains 32+31= 63 chromosomes in their somatic cells.
This chromosome number in mules are uneven for meiosis to occur because meiotic division requires that an even number of homologous chromosomes pair together in a process called SYNAPSIS during prophase I of meiosis I. This is impossible in a mule because of the uneven number of chromosomes in its cells.
Also, during metaphase of meiosis, the homologous chromosomes need to be properly aligned at the equator for separation to occur. This is also impossible in a mule considering the number of chromosomes that don't add up.
Due to this reason of unevenness in the number of chromosomes present in a mule, meiosis will not occur and if meiosis (gamete formation) does not occur, reproduction cannot take place. Therefore, the mule is a sterile species i.e. cannot produce offsprings via sexual reproduction.
D)independent
Explanation:
An independent variable is a variable that is changed to test the prediction in an experiment. Independent variables are the cause in an experiment. They are the ones that produces the effect.
- Changing independent variables produces different effects in an experiment.
- These effects are the dependent variables
- Independent variables do not depend on the outcome of the experiment.
- They are the ones that determines how a reaction proceed and what might likely happen.
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There's no land at the North Pole Instead it's all ice that's floating on top of the Arctic Ocean. ... Multi-year ice is thicker and has survived at least one melt season, whereas first-year ice is much thinner. Arctic sea ice usually reaches its minimum around mid-September each year.
