Which type of succession (primary or secondary) is going to have the biggest impact on an ecosystem?

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.

Amoeba sisters video recap pedigrees

Why do we perceive objects as retaining their brightness under different lighting levels?