A student finds a puddle of water in a garden and takes a sample. He wants to perform an experiment to determine if there are living things in the water. How could he collect data that would provide evidence of living things? A.
examine the sample under a microscope to see if cells are present

B.
measure the weight of the sample over several days to see if the weight increases

C.
observe the water closely to look for particles that are large enough to be seen

D.
determine the amount of oxygen and carbon dioxide present in the water