Which is the best and complete description of an organelles purpose in a cell? Hint - what did organelle mean? what do they do?

When analyzing tree rings, what do scientists assume a thin ring indicates?

What percentage of light hits earth's surface directly?

Ronald wants to see if a new shower cleaner works better in removing soap than his old cleaner. he uses the new cleaner on one half of the shower tiles and his old cleaner on the other half. identify the independent and dependent variables in this experiment. enter your answer in the space provided.