A student is conducting an experiment to determine how far a ball will roll down a ramp based on the angle of incline. What are the three possible controls for this experiment?

Which organelles are labeled d, and what is one feature that distinguishes them from the other labeled organelles chloroplasts the only organelles that produce sugars from sunlight mosomes, only found in animal and bacterial cells centricles only found in animal cells mitochondra, the only energo-generating structures found in cells

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic

This is a biological reaction due to a stimulus. i need this quickly !