Which element is found in proteins but not carbohydrates or lipids and why cant they be found in them?

Idont understand by supporting the plant and holding the leaves up to the light. question 3 options: tap or fibrous root flower petals herbaceous or wood stems leaves with stomata

Johnny rode his bike to a friend's house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was not able to play. what was his displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point

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