Shown below are the dna scans for three frogs that look alike. which frogs are identical twins?
a. frogs a and c
b. frogs b and c
c. frogs a and b
d. it cannot be determined.

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