2. In order for the lagging strand to elongate during DNA replication, it must
A) be synthesized in a 3-5 direction.
B) progress towards the replication fork.
C) use short RNA primer to proceed.
D) be continuously synthesized by DNA polymerase.

B) progress towards the replication fork.

Explanation:

Replication fork is a point on the parental DNA where the DNA is being unwound and separated; and the separated strands are being replicated. Synthesis of a new DNA strand occurs in a 5' -> 3' direction, as the DNA strand serving as the template is read from its 3' -> 5' direction. During replication, two strands of DNA are synthesized: The leading strand is synthesized continuously in the same direction as the replication fork movement while the lagging strand is synthesized discontinuously in the direction opposite to the direction of fork movement, that is, towards the replication fork. The lagging strand is synthesized in short fragments known as Okazaki fragments.