Which of these labels matches the structure of the partial RNA strand shown?

(A) I. phosphate; II. ribose; III. nitrogen base
(B) I. phosphate; II. nitrogen base; III. ribose
(C) I. nitrogen base; II. phosphate; III. ribose
(D) I. ribose; II. nitrogen base; III. phosphate
(E) I. ribose; II. phosphate; III. nitrogen base
  1. Correct Answer: A


    The five-carbon ribose sugar (II) and the phosphate group (I) make up the backbone of the RNA strand. The nitrogen bases (III) are attached to the ribose sugars.

Test ID: 1331
Source: SAT Biology Practice Tests