The protects the body from foreign substances and cells.
a. immune system
b. endocrine system
c. urinary system
d. respiratory system

The immune system protects the body from foreign substances and cells. Our immune system protects us from tiny organisms such as bacteria, parasites, and fungi which cause infections.

Correct A. The immune system

Good luck with your studies, I hope this helps~!

Not true , they can fall or something

Ithink it’s d. that should be correct.