Because while you're preagant your have so much presure on it it doesnt have a choice where as weight gain everything grows with it. Think of it this way, if you've ever felt a pregants womans belly its harder than usual. If you touch someones belly that is bigger its more smoshy (I know thats not spelt right)
The answer is A.
Twins form in one of two ways:
Identical twins occur when a single fertilized egg splits into two.
Fraternal twins occur when two, separate eggs are fertilized by two, separate sperm.
