10) Which of these are purines?
a. adenine and guanine
b. thymine, cytosine, and uracil
c. thymine, adenine, and cytosine
d. thymine, uracil, and adenine
a. adenine and guanine
b. thymine, cytosine, and uracil
c. thymine, adenine, and cytosine
d. thymine, uracil, and adenine