Which of the following statements about protists are true? a. they are typically found in moist environments. b. they are all unicellular. c. they have a nucleus. d. they are all multicellular.

D. is the correct answer

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".