Answer: Hypothesis
Step-by-step explanation:
For each experiment involving nanotechnology, Gerry and Lena will test a hypothesis.
Gerry and Lana will use the Scientific method for their nanotechnology research and a key stage in the scientific method is to come up with a Hypothesis.
A hypothesis gives a researcher direction because it is a theory that they formulate that is meant to explain the phenomenon that they are researching.
They will then test this theory to either disprove or approve it and in so doing will be able to come up with conclusions to the research. Gerry and Lana will therefore have to test a hypothesis for each experiment in order to continue with their research.