Question

In answer to the question, "When a plant grows, where does the material come from?" the ancient Greek philosopher Aristotle hypothesized by logic that all material came from the soil. Which of the following experimental tests might best prove Aristotle's hypothesis to be correct or incorrect?

A Stop watering the plant to see if t he mass of the water contributes to the long term growth of the tree.
B Cover the tree with a black bag.
C Grow the tree in a pot and measure the mass of the soil before and after the tree grows to a certain height.
D Aristotle was one of the greatest philosophers of all time; thus no test to any of his hypothesis is necessary.

Answer 1

Answer: C. Grow the tree in a pot and measure the mass of the soil before and after the tree grows to a certain height

Explanation: When testing an hypothesis, which is a prediction of the outcome of an experiment, it is vital to keep all other factors, that can affect the outcome of the experiment, constant; so that any outcome can be attributed (or disregarded) to the variable being tested.

In this case, the variable being tested is the soil, and so all other factors such as water, air, sunlight, etc. should be kept constant.