What is and allele I need help pls

Which macromolecule catalyzes chemical reactions this be considered enzyme chemical reactions thus he considering enzymes

Is genetic diversity the same as genetic variation?

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