When one nucleotide contains cytosine, what type of base is the cytosine attached to on the opposite nucleotide strand?

Consider darwin's first writings on the theory of natural selection. an important point of darwin's essay on the principle of population, written in 1798, was a peer's observation that in nature plants and animals produce far more offspring than can survive, this observation can be attributed to a) charles lyell. b) thomas malthus. c) jean-baptiste lamarck. d) johann friedrich meckel.

Aristotle classified animals according to their a. habitat and mating behavior c. mating behavior and relatedness b. habitat and physical differences d. physical differences and mating behavior

Which particle controls what element an atom is?