Final answer:
A hypothesis in biology must be testable in order to be scientifically valid.
Step-by-step explanation:
A hypothesis always has to be testable.
A hypothesis is a proposed explanation or prediction about a phenomenon or set of observations. In the scientific method, a hypothesis must be testable, which means that it can be proven right or wrong through experiments or other scientific techniques.
For example, if a biologist hypothesizes that increasing the amount of sunlight will lead to plant growth, they can design an experiment to test this hypothesis by exposing plants to different amounts of sunlight and measuring their growth.
Learn more about Hypothesis testing in biology