The absorption of heat by the breaking of hydrogen bonds, think homeostasis or h<span>ypothalamus.</span>
Answer:
The independent variable are the vitamins .
The dependent variable are the rats.
Explanation:
The vitamins are the independent variable because they are are controllable. You can control how many vitamins the rats will be given.
D. They had to see if this new idea fit the evidence they found in their experiments.