HOw could overuse of household disinfectants weaken the immune system

I'm assuming there are options so...

I believe the correct answer is

D. By reducing exposure to pathogens and the creation of specific memory cells

It will reduce exposure to certain pathogens and prevent you from getting sick which is good, but if you don't get those pathogens, when your body does encounter it again, your Memory T cells will. it know how to fight it off.

the answer would be knowledge about cars!

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.