If an dna molecule is compared to a spiral staircase, what parts make up the steps. a)pairs of nitrogen bases. b)sugar and nitrogen base. c)sugar and phosphate. d)pairs of sugars.

Which statement correctly describes a way that mutations increase the likelihood that a species will survive in a changing environment

The wings of insects, birds, and bats evolved independently but carry out similar functions. this is an example of a. analogous structures. b. embryonic structures. c. vestigial structures. d. homologous structures.

Idon’t know the answer and i’ve been stuck on it for a while now skskskskks