I'm going to assume your male. When this is done it mainly to check to see if exertion of slime kind causes your testes go through the foramen of the pelvis into the abdomen. Trust me this is a very true and very painful condition.
The biopsychosocial perspective is an integrated approach to psychology that incorporates three different perspectives and types of analysis: biological, psychological, and social-cultural.
The bottom because that's where all the cold air falls and collects in.
That is good for their health.
Sit ups, because you are using your core.