Someone help me give me the answer

Mario performed an experiment to determine if photosynthesis was affected by the amount of light that a plant received. what could he have done to increase the validity of his data? reduce the number of plants. remove the 1 hour group. add a 0 hours control. measure the oxygen in liters

Someone me with this: a mineral' is determined by its actomic structure.

Explain how scientists use geologic time to determine the age of landforms.