7. Which of the following changes could be associated with either a chemical change OR a physical change?
a. The change cannot be reversed
b. Bending of metal
c. New substances formed
d. Change in color

a: chemical change because the change cannot be reversed.

b: physical change because the action can be reversed.

c: chemical change.

d:chemical change.

any change that cannot be reversed is a chemical change and any change that can be reversed is a physical change.

4,524 gallons

Step-by-step explanation:

The volume of any cylinder is 

 π (radius)² (height) .

The pool's radius is 1/2 its diameter = 8 ft.  So its volume is

 π (8 ft)² (3 ft)

= π · (64 ft²) · (3 ft)

= π · 192 ft³

= 603.2 ft³ .

(603 ft³) · (7.5 gal / 1 ft³) = 4,524 gallons

Hope this helps :D