What did darwin observe about finches in the gal�pagos islands?
a. their feathers were adapted to match their environment.
b. their beaks were adaptations related to the foods the finches ate.
c. they had homologous body structures with other flying vertebrates.
d. they were unrelated to mainland bird species.

B. their beaks were adaptions related to the foods the finches ate
Darwin concluded that the finches descended from a common ancestor, yet with time, the finches' beaks adapted to make food easier to access.

A) The positive linear relationship between body age and ammonia concentration only holds for early stages of decomposition.

Explanation:

The concentration of ammonia in the vitreous humor in the eyes of the cadavers has provided some considerable help in forence reports and other areas when it is necessary to know what was the postmortem interval of that body. However, this aid is only effective for a limited time because the positive linear relationship between body age and ammonia concentration is valid only for early stages of decomposition. After time has elapsed, this concentration is difficult to measure and the determination of postmortem time is impossible to determine.