Can the world run out of carbon?

1) True

2) True

3) False

4) True

Explanation:

1) True. Nucleotides are the monomers of the polymeric chain. DNA is formed by two complementary polymeric strands.

2) True. Each DNA strand has a polarity or directionality and it is determined by the direction that nucleotides are pointing. Each nucleotide will have a 5' end phosphate on one side and a 3' hydroxyl end on the other. One strand will have 5'-3' direction and the complementary strand 3'-5'.

3) False. There are four different nucleotides that can be incorporated into a DNA strand, these are: Cytosine, Guanine, Adenine and Thymine.

4) True. Hydrogen bonds between Cytosine-Guanine (C-G) and Adenine-Thymine (A-T) in different strands hold the complementary DNA chains together.