Neurotransmitters are the chemical molecules, which help in transfer of the signals from one neuron to another. Inside the neurons, the signals are transferred as electrical signals, but at junction of two neuron, which is known as synapse, the signals are transferred in chemical forms.
These neurotransmitters have a definite shape and are recognized by the receptors present in the receptor site of the succeeding neuron. The neurotransmitters from the synapse binds to the receptor site of the receiving neuron. binding of the neurotransmitter to the receptor causes excitation of the receiving neuron, which also known as postsynaptic neuron.
Hence, Like a key in a lock, the shape of the neurotransmitter must bind with the receptors of the receiving neuron.
<h2>Answer </h2>
Neutral Variation
<u>Explanation</u>
Point mutations in noncoding regions of DNA result in neutral variation. The alleles which neither considerably sum to nor exceedingly lower from body consistency. It is the accumulation of such alleles located within a community that can be explained as expressing neutral variation. Neutral Variation implies in various alleles that are existing at an assigned genetic locus because those alleles are not distinct by natural selection.
In sperm cells<span>, four haploid </span>gametes<span> are </span>produced<span>. In egg </span>cells<span>, </span>meiosis<span> results in a single haploid</span>gamete<span>, with the remainder of the genetic material lost in the formation of three nonviable polar bodies.</span>
B. Soil Contamination
All the other answers are talking about clean and pure things while this answer is the only negative one. So B is your answer.
