Sally and Tim Were Planning on Starting a Family

Multiple Choice

Sally and Tim were planning on starting a family. Sally's extended family have several sets of dizygotic twins. When speaking with their doctor, Sally asked what could cause her to have dizygotic twins. The doctor informed her that the likelihood of having dizygotic twins will be determined by _____.

A) her husband's genes
B) her genes
C) the environment
D) an interaction between her genes and the environment