Which of the Following Directly Demonstrates That Genetics Play an Important

Which of the following directly demonstrates that genetics play an important role in obesity?

A) Obesity rates in the U.S. and Canada have increased rapidly in the past few years as a function of obese individuals producing offspring.
B) Scientists have determined that most of the time, a single gene appears to determine obesity.
C) Technological advances have decreased the need for daily physical activity in certain people who carry the obesity gene.
D) Identical twins raised apart are about as similar in body mass as identical twins raised together.