D. Our bodies need less oxygen during stressful situations
The goal of flexibility exercises is to allow you to move muscles. And with flexible muscles this will help you prevent injuries such as muscle aches or back pain.
Answer:
An immune deficiency disease occurs when the immune system is not working properly. If you are born with a deficiency or if there is a genetic cause, it is called primary immunodeficiency disease. There are more than 100 primary immunodeficiency disorders.