Biology

A scientist is investigating the effect of caffeine on the heart rate of mice. She divides the mice into two groups: Group A receives a caffeine solution, while Group B receives plain water. Both groups are kept under identical conditions, including the same diet, temperature, and living environment. The heart rates of the mice are measured after one hour.

After measuring the heart rates, the scientist finds the following average results:

1. Group A (caffeine): 150 beats per minute

2. Group B (water): 120 beats per minute