Pls Help Marking brainliest if it's correct pls explain

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.

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

Why has two different alleles for the same trait?