Who can help me in biology!!

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

Which process the first step in making a protein from dna intrsuction

How can the energy stored in the photosynthetic organism be used? : "(