1. For which discovery about DNA do Watson and Crick receive credit? A. DNA is the molecule that genes are made of.
B. The amount of adenine equals the amount of thymine in an organism.
C. Phosphate-pentose bonding along the nucleotide backbone is covalent.
D. The shape of DNA is a double helix.

Why does meiosis produce cells with half the chromosomes? o a. most of the chromosomes are not necessary to keep an organism alive. b. a gamete needs only half the number of chromosomes because two gametes join together. o c. it makes the gametes easier to move around in the organism. o d. it is faster to produce gametes with fewer chromosomes.