The student performed an experiment to test his hypothesis about sunlight and plant height using two plants. He kept everything the same between two tomato plants except he exposed them to different amounts of sunlight. He also used a third plant as a control group, or a group in which no variables are manipulated to confirm the results. Roberto critiqued the work. Which problem did Roberto most likely identify? The sample size is too small. Too many variables are manipulated. It is not possible to keep the conditions the same. Controls should only be used in studies of animals.

The sample size is too small

Explanation:

The problem most likely identified by Roberto would that the sample size is too small.

A small sample size during an experimental study would decrease the statistical power of the data from such an experiment and increase the likelihood of making an error - type II error. Type II error occurs when the null hypothesis is confirmed instead of being rejected and this often occurs due to small sample sizes.

The student used just a tomato plant for each study group. This represents a small sample size. Hence, the main reason for criticizing the experiment performed would be due to the small sample size.

"griffith's experiment discovering the "transforming principle" in pneumococcus bacteria. griffith's experiment, reported in 1928 by frederick griffith, was the first experiment suggesting that bacteria are capable of transferring genetic information through a process known as transformation." - griffith's experiment.