Does anyone know this?

Which of the following elements does soil need in the largest quantities to sustain plant life? a. copper b. iron c. nitrogen d. zinc

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

In which of the following relationships is one organism always benefited while the other organism is always harmed