Answer: Hypothesis
Step-by-step explanation:
A hypothesis is a proposed explanation for any phenomenon. The hypothesis is given before the experiment is being performed.
In this case the it is said that presence of water could accelerate the growth of mold.
This is a hypothesis because it has not been proved by the experiment it is just a proposed explanation which is given before the experiment.
This is known as the hypothesis which can be accepted if experimentally proved and can be rejected if not proved.