7. A protein is a long strand of assembled in the . a. amino acids—nucleus
b. amino acids—ribosomes
c. RNA—nucleus
d. RNA—ribosomes

8. Each amino acid is coded for by .

a. a single DNA base
b. a sequence of three RNA molecules
c. a sequence of three DNA bases
d. a sequence of three proteins

9.What is NOT true about RNA?

a. It stands for ribonucleic acid.
b. It helps DNA make proteins.
c. It has all of the same bases as DNA.
d. There are two types: messenger RNA and transfer RNA.

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.