What statement best describes an independent variable? .
a. the factor that's changed by the experimenter and impacts the dependent variable.
b. the factor that's not changed by the experimenter and is impacted by the dependent variable.
c. the factor that does not change, but impacts the constant in an experiment.
d. the factor that's changed by the experimenter and impacts the constant in an experiment

the transfer of energy between two molecules spaced just nanometers apart plays a key role in many technologies, including photovoltaics, quantum information systems, lighting, and sensors, as well as in biophysics to measure nanometer distances and in photosynthesis. but an open question in this area is what effect, if any, the surrounding photonic environment has on this nanoscale energy transfer. by designing and performing a carefully controlled experiment to answer this question, scientists have settled the debate and found clues to improving the efficiency of many of the technologies that rely on this process.

explanation: