Answer:
21 centimeters
Explanation:
As the table shows: 1 centimeter = 10 millimeters,
so that would mean 40 millimeters is 4 centimeters since 40/10=4
You then subtract 25 - 4 (centimeters) which = 21 centimeters.
Meaning Naomi's guinea pig is 21 centimeters longer than her fish.
("/" means division)