An example of a secondary source is:
a. an encyclopedia article
b. an autobiography
c. a census report
d. a diary

A

Explanation:

I believe the answer is A, since an encyclopedia article is not coming directly from a person, unlike a diary, which is a primary source.

answer; the above answer to the above statement is (true)

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.