Alright, so mass is a property of a physical body. During physical changes, such as acceleration, force, etc, the mass stays the same since we are not affecting its physical shape, just where it is physics wise. So yeah mass is conserved during a physical change.
(This is very confusing I'm bad at explaining things sorry)
Answer:
C
Explanation:
In 1839, Theodore Swhwann, a German Zoologist examined bits of animals under a microscope and observed that animals were composed of cells.