2. A submarine is able to raise and lower itself underwater. A rock sinks when it is dropped in a
pool because it is denser than water. A piece of
wood floats in the pool because it is less dense
than water. What could the submarine change in
order to sink or float? Choose all that apply.
A. the submarine's volume
B. the submarine's mass
C. the state of the surrounding water
D. the mass of the surrounding water

I think it's the state of the surrounding water because if the water holds impurities it will float and if it doesn't have impurities it will sink

is there multiple choice answers?

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e