Question

Which best describes an experiment?
In a lab a scientist measures the height of roses that received different fertilizers.
A scientist measures the speed at which a cheetah travels while it is hunting.
A scientist measures the rate at which a population of wild geese reproduces.
A scientist measures the width of a certain type of maple leaf throughout a forest.

Answer 1

A: In a lab a scientist measures the height of roses that received different fertilizers.

An experiment must include variables. The other three are just measurements, but since the scientist is varying the types of fertilizers used, this better describes an experiment. It is also done in a controlled environment (in a lab) which helps to eliminate other uncertainties.