问题详情

According to paragraph 3, what is the advantage of hydroponics for research on nutrient deficiencies in plants？

A．It allows researchers to control what nutrients a plant receives.

B．It allows researchers to observe the growth of a large number of plants simultaneously.

C．It is possible to directly observe the roots of plants.

D．It is unnecessary to keep misting plants with nutrient solutions.

请帮忙给出正确答案和分析，谢谢！