How Do We Know That Genes Play a Role in Pubertal

Multiple Choice

How do we know that genes play a role in pubertal timing?

A) Because researchers have identified a gene that triggers puberty and can track the timing.
B) Because identical twins experience menarche at about the same time, whereas fraternal twins can vary by a year or more.
C) Because there are no other consistent reasons for why puberty occurs.
D) Because siblings of all ages experience puberty at about the same age.