Carlie Is the Proud Mother of Two Children

Multiple Choice

Carlie is the proud mother of two children.Her oldest is 2 years old and the youngest is now 6 months old.Both are girls.Carlie is amazed at how different they are.The oldest is reserved and quiet.Her youngest is outgoing and happy most of the time.These differences can be attributed to

A) differences in temperament.
B) differences in gene expression.
C) differences in parenting style.
D) a shared genome.