Answer:
Neurotransmitters
Explanation:
Neurotransmitters are the chemicals present in the body used for the propagation of action potential. These neurotransmitters are also known as the body chemical messengers.
Neurotransmitters are stored in the neural cells. These chemicals are generally released when the cell is stimulated by the specific signal. The effect of neurotransmitter may be excitatory or inhibitory.
Thus, the answer is option (4).
D. Phenotype because a phenotype is observable traits
The rift<span> is a narrow </span>zone<span> that is a developing divergent tectonic plate boundary, in which the </span>African<span> Plate is in the process of splitting into two tectonic plates, called the Somali Plate and the Nubian Plate, at a rate of 6–7 mm annually.</span>
Answer: The simplest way is to determine if a strain is mutant is observing morphology, growth rate, double time, etc but it is accurate if you can prove if the strain is deficient in one aminoacid or can't metabolize lactose, etc.
Explanation: A wildtype strain functions normally, for example, can metabolize as a carbon source, glucose, lactose and other sugars, can synthesize all the aminoacids requered for protein synthesis, etc. If a strain suffers a mutation and it is inheritable, the strain become a mutant. Since several mutations can be silent ones, only those that interfere with a process, can be assesed easyly.
For example, if you have several strains and put them in a lactose medium, but some of them cannot growth means that are lactose mutants. Those strains could carry a mutation in genes that encode lactose degrading enzymes or in regulatory genes of the lac operon, etc.
