Why are bacteria a necessary part of the nitrogen cycle? . . a. living things cannot use atmospheric nitrogen.. . b. living things cannot use the nitrogen in plants.. . c. bacteria are the main nitrogen reservoir.. . d. bacteria are the main nitrogen transpirators..

Abird flies by moving its wings up and down. which two systems are most directly responsible for the movement of a bird's wings? a. skeletal and muscular systems b. respiratory and muscular systems c. skeletal and digestive systems d. respiratory and digestive systems

Several bodily responses are described below. for each response, determine what caused the change in homeostasis. body starts to sweat breathing rate increases amount of saliva produced changes body starts to shiver

Kendra has the ability to cover a distance in a short period of time. she is said to have a lot of agility power strength