An isotope is an atom of the same element, but with a different number of neutrons. How many stable isotopes of Boron can you build and what is the mass of each isotope?

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