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?

a.) the sample size is too small.
b.) too many variables are manipulated.
c.) it is not possible to keep the conditions the same.
d.) controls should only be used in studies of animals.

The correct answer would be A.) The sample size is too small.

Sample size refers to the total number of observations or participants taken into consideration while performing an experiment or in a study.

It is suggested that the sample size should be kept as high as possible.

It helps in increasing the reliability, precision, and reproducibility of an experiment.

As the student used only two plants for the experiment so, we can not be sure if the results were scientific or just a matter of chance.

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.