Cara and chuck were looking at pond water through a microscope. they saw small square crystals in their slide. cara wondered what it was. chuck said it could not be any living thing because it was not a) round. b) moving. c) small enough. d) made of cells.

The correct answer is D) made of cells.

Explanation:

Let me elaborate:

A microscopic entity does not have to move to be alive and functional therefore this answer would not make senseAnything can live no matter the size of the creature living, in fact depending on how the living entity survives in general and it's basic needs some creatures likely find it easier to be at a large size or small size and some may find it excrusiatingly hard to survive at there current size, but most of the time in fact a lot of the time these creatures adapt to there surroundings and surviving is much easier no matter how much of a hassle it isAnd finally just because something isnt round doesnt mean it is not alive.

Therefore the answer is D. Made of cells.

Where are they though?

Sorry its not enough info