The earth consists of a variety of different organisms. despite their diversity, however, some similarities on the structural and metabolic levels may be seen. these similarities can be attributed to a. similarities among organisms in their proteins and nucleic acids. b. the ability of organisms to readily adapt to sudden environmental changes. c. similarities in organisms' habitats and niches. d. the ability of all organisms to interbreed and produce new species.

The answer is A.

Sorry if im wrong .

A. similarities among organisms in their proteins and nucleic acids.

Explanation:

Presence of some common genes that have been conserved during the course of evolution leads to presence of shared proteins in otherwise diverse organisms. Since genes are expressed in form of protein and protein regulate the morphological expression of organisms; presence of common protein in organisms give them morphological similarities.

d we did this already