If two organisms possess similar structures that serve similar functions but don't possess a common ancestor that shared that structure, then the structures are classified as
a. vestigial.
b. morphologies.
c. analogous.
d. homologous.

C. Analogous

Explanation:

For example, the wings of a fly, a moth, and a bird are analogous because they developed independently as adaptations to a common function—flying.

Analogous organ.

Explanation:

Analogous organ may be defined as the organs that have similar structure and function but not share a common function. This type of organ shows convergent evolution.

Analogous organs are opposite to the homologous organ. For example: Wings of bats, insects and birds have similar structure and function but does not have a common ancestor, they are analogous organ.

Thus, the correct answer is option (C).

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

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