A student observed five cells under a microscope and concluded that all cells in the tissue are the same size. Why is the conclusion weak?

Correct answer: The sample is small and possibly unrepresentative

Direct answer: Option A, the sample is small and may not represent the whole tissue. Observing five cells can describe those five cells, but it cannot safely establish that every cell in a large tissue has the same size. Cells may differ because of location, development, function, or natural variation. A stronger investigation would measure many more cells from several regions, use a calibrated scale, and report the range or variation as well as a summary. Option A is correct because a representative sample is needed for a broad conclusion. Option B is wrong: microscopes are specifically used to observe cells. Option C is wrong: cell size can be measured using a scale or calibrated image. Option D is wrong because five observations are not automatically a large sample for a tissue. Memory cue: a small sample supports a limited claim, not an “all” claim.