Answer:
C. Critical period.
Explanation:
Critical period:
In developmental biology, ciritical period is also known as sensitive period which is defined as a period or stage of maturation in the organism's lifespan in which nervous system is more sensitive to various environmental stimulus. Means, brain cell connections are more receptive to influence from surrounding environmental factors. Our body's many cruical functions including behavior are established during critical period with irreversible impact.
Although the operation of natural selection requires that genotypes differ in fitness, for some geneticists it seems easier to understand natural selection than fitness. Partly this reflects the fact that the word “fitness” has been used to mean subtly different things. Here I distinguish among these meanings (e.g., individual versus absolute versus relative fitness) and explain how evolutionary geneticists use fitness to predict changes in the genetic composition
Monera, Protista, Fungi, Plantae and Animalia.
