Here's why:

* Testable: A hypothesis must be something that can be tested through experiments or observations.

* Idea or Explanation: It's a proposed explanation for a phenomenon or a prediction about the relationship between variables.

* Leads to Scientific Investigation: A hypothesis is the starting point for a scientific investigation. Scientists design experiments or gather data to test the hypothesis and see if it holds true.

Example:

* Hypothesis: Plants grow taller when exposed to more sunlight.

* Testable: This can be tested by growing plants in different light conditions.

* Leads to Investigation: The scientist would design an experiment where some plants receive full sunlight, others partial shade, and others no sunlight. They would then measure the height of the plants after a set period.