Question

why cant the teacher test the amount of water and the amount of sun? the plants would grow too fast. actually, he can test both things in the same experiment. at the end, he would not know which caused the plants to grow differently. the plants would not grow. rewatch

Explanation:

In a scientific experiment, to determine the effect of a variable, other variables should be controlled. If both water - amount and sunlight - amount are changed simultaneously, it's impossible to tell which variable caused the change in plant growth.

Answer:

At the end, he would not know which caused the plants to grow differently