Answer:
A null hypothesis would be that caffeine doesn't stimulates sunflower plants to grow taller.
Step-by-step explanation:
Null hypothesis: In research methods, the term "null hypothesis" is described as a type of hypothesis that proposes that there's no difference between specific characteristics of a particular data gathering process or population.
Function: The main aim of "null hypothesis" is to prove whether or not a specific test or study is supported and is separated from the researcher's own decisions and values. It is responsible for providing a way to a given study or test and is represented by H0.