Your metabolism is the muscle activity that burns calories.
D I believe that’s the answer
Answer:

Cell wall : Plant cells have a cellulosic cell wall, which is absent in the case of animal cells.
The plasma membrane serves as the outermost boundary for an animal cell.
Answer:
The mass
Explanation:
The gravitational field of an object with mass increases as its mass increases. So, a larger object, like the earth, has a stronger gravitational field than a smaller object, like the moon.
There are more factors that may play into this however.