The amino acids in a protein are held together by what type of bond?

Which diagram best represents the chromosomes that would be found in a two new skin cells produced as a result of this process?

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

Why do mountaineers become breathless as they reach high altitudes