A weakened immune system may be caused by O an overproduction of lysozymes.
O muscle disorders.
O immunodeficiency disorders.
O complement systems in the blood.

immunodeficiency disorders,and etc

Explanation:

because immunodeficiency disorder- is a disorder that helps you attract more viruses and illness. it can bae acquired trough birth or dieting or lack of energy foods...

he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.