Friends, parents, wife/husband, siblings, teachers.
Answer:
A. Crunches
Explanation:
Crunches are an exercise which you lift your upper back from the ground(or head) in a laying position on your back. This exercises your abdominal muscles, which is around your tummy area.
The backpack's main force that it it is exerting on the body's back and hips is coming from gravity, and can pull the spine downwards. This is why it's important to ear both straps.
Twins can either be Mono-zygotic (Identical) Which means they develop from one zygote which splits and forms two embryos, or Di-zygotic (fraternal) meaning that each twin develops from two different eggs and each egg is fertilized by a different sperm cell.
I am not sure which one may be your answer.
But
I Hope This Helped!
