Question

By directing the synthesis of​ proteins, DNA controls the shape and physical characteristics of our bodies.

A.
past participle
B.
infinitive
C.
present participle or gerund
D.
simple form

Answer 1

directing is pres pert'ple of "to direct" = infinitive

a gerund or verb used as a noun ...

Answer 2

The verb directing is in the gerund​ form. So the answer is C. present participle or gerund