Question

how many bases make up the human genome?
a about 3,000,000
b 4
c about 3,000,000,000
d about 20,000

Explanation:

The human genome is composed of DNA, and it contains approximately 3 billion base pairs. Option a (3,000,000) is too small (it's about the size of some bacterial genomes). Option b (4) refers to the number of nucleotide bases (A, T, C, G) but not the total number of base pairs in the human genome. Option d (20,000) is approximately the number of protein - coding genes in the human genome, not the number of base pairs.

Answer:

C. about 3,000,000,000