Question

A scientist did an experiment using a chemical inhibitor that stops photosynthesis for a certain type of plant. He grew two plants, giving the chemical to one plant and not to the other. Both plants were given equal amounts of water and sunlight. He then measured the growth of both plants as shown in the table below.

Date Height of
Control Plant
(cm) Height of Plant
Treated With
Chemical Inhibitor
(cm)
June 5 8.3 8.6
June 7 8.7 8.7
June 9 9.2 8.7
June 11 9.6 8.7

Why did the plant that could not photosynthesize stop growing?
A.
It did not have enough other plants to consume for food.
B.
It did not have enough food for building materials.
C.
It did not have enough light to grow.
D.
It did not have enough water to grow.

Answer 1

B. It did not have enough food for building materials.

The inhibitor prevented photosynthesis, so the treated plant couldn't make sugars and other organic molecules needed as energy and raw materials for growth. Water and light were supplied equally, so lack of photosynthetic products—not light or water—caused growth to stop.