Measurements of a plant's growth over a two-week period represent?

Question

inferences.

variables.

hypotheses.

data.

Answer 1

Data, and only data.  A variable would be something used such as more or less water see if it affected the growth.  You could "infer" from this that it either did or did not, and develop a hypotheses that might lead to a theory about plant growth.

Answer 2

data