Explain how the isotopes of an element differ.

a. they each have a different number of electrons in their outermost energy level.
b. they each have a different number of protons in their nuclei.
c. they each have a different number of neutrons in their nuclei.
d. they each have a different charge.

Which of these statements best describes the st. lawrence seaway? the st. lawrence seaway connects the st. lawrence river with the arctic ocean. the st. lawrence seaway provides an important trading route between the u.s. and mexico. the st. lawrence seaway provides an important trading route for the u.s, but has little value for canada. the st. lawrence seaway connects the great lakes, the st. lawrence river, and the atlantic ocean.

What is the most appropriate method of gaining weight (muscle mass)

When you run, you begin to breathe heavier and faster. your heart beats more quickly, bringing more oxygen to your cells. which organ systems are working together here?