What are the principles behind FFA and how does the group teach and reinforce them? I really need this answer! Please help!

The body is protected against harmful flu viruses by

Which statement describes a way in which the digestive and excretory systems work together? a. the nephrons absorb nutrients from food going to the large intestine. b. the excretory system balances blood gases in the small intestine. c. the intestinal villi filter blood and send wastes to the bladder. d. the excretory system balances the salts and water obtained from digested food

Isotopes of the same element have differ in their