Your Professor Mentions in a Lecture That Activity Level Follows

Your professor mentions in a lecture that activity level follows a polygenic pattern of inheritance.You,having already read Chapter 2 in your textbook,realize this means that

A) activity level is a recessive trait.
B) a single gene determines activity level.
C) there is no evidence of a genetic influence on activity level.
D) activity level is determined by the combination of many genes.