Genetic adaptation
a. occurs at the individual level throughout an individual’s lifetime.
b. occurs at the population level via natural selection.
c. involves using material culture to make living possible in certain settings.
d. occurs at the individual level during childhood.

b. occurs at the population level via natural selection

Explanation: Genetic adaptation can be described as the change or adjustment in structure or habits by which a species becomes better able to function in its environment, occurring through the course of evolution by means of natural selection.

An example of genetic adaptation at a population level is the encouragement of bipedalism in humans.

The degree of adaptation that can occur in a population is limited by the amount and kind of genetic variation in a population. If a population is suited to adapt and survie in its habitat it will undergo very little genetic adaptaction (prime example is the cockroach). If a population on the other hand is not able to adapt to its habitats´circumstances the popuation will undergo genetic variation in order to survive and ensure the continuation of the species. ( prime example are the birds Darwin studied in the Galapagos Islands)

Animals show anatomical adaptations—e.g., the body of the fish is suited to life in the water; the body of the bird is adapted for flight; and the land mammals show a wide variation in the structure of limbs and body that enables some to run swiftly, some to climb, some to swing from tree to tree, some to glide through the air, and others to jump.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.