The answer is D.
A retrovirus is any of a group of viruses that characteristically carry their genetic information in form of RNA. These viruses have an enzyme called reverse transcriptase from which they derive their name because they follow the first step of the central dogma backward thus "retro" which means backward.
Reverse transcriptase makes DNA from RNA template thus reversing the usual pattern of transcribing RNA using DNA as the template.
The central dogma of molecular genetics summarizes steps of protein synthesis as DNA → RNA → protein. But retroviruses have modified the process to be RNA → DNA → RNA → protein.
Beryllium. The image represents beryllium.
Excitatory neurotransmitters cause the neuron to fire, and Inhibitory neurotransmitters cause the neuron not to fire.
Impulses are the signals passed from one neuron to another on the action of a stimulus. The impulses passed can be electrical or chemical. Neurotransmitters are the chemical molecules that help in the transfer of impulses between two neurons.
Chemicals like epinephrine, norepinephrine, and glutamate when released from the synaptic cleft of one neuron activate the receptors of other neurons, thereby initiating the other neuron to fire. These chemicals are called excitatory neurotransmitters.
Chemicals like GABA and glycine, when released from the synaptic cleft of one neuron do not activate the receptors of other neurons and hence the neurons will not fire the impulse. These chemicals are called inhibitory neurotransmitters.
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Non-random mating is assortative mating. It is a pattern and form of sexual selection in which individuals with similar phenotypes mate with one another more frequently than would be expected under a random mating pattern. non-random mating can act as an ancillary process for natural selection to cause evolution to occur. It’s also bad for evolution because any departure from random mating upsets the equilibrium distribution of genotypes in a population. Recombination is a process by which pieces of DNA are broken and recombined to produce new combinations of alleles. recombination is important to somatic cells in eukaryotes because it can be used to help repair broken DNA. recombination by itself does not cause evolution to occur. Rather, it is a contributing mechanism that works with natural selection by creating combinations of genes that nature selects for or against. Non-random mating affects the evolution more than recombination
