Whats an entire group of muscles that work together called?

Which of the following statements is true? 1. the mantle of the earth is made of solid nickel and iron. 2. the crust of the earth is made of solid nickel and iron. 3. the inner core is made of solid nickel and iron.

Which element forms the basis of all organic organisms a carbon b oxygen c hydrogen d nitrogen

Explain how sequences of amino acids in proteins can be used to reveal relationships among organisms.