Answer:
C (see below)
Explanation:
Using the process of elimination:
A) leaf colors and root lengths.
It says that "Antonio and Addie want to know if perfume fumes affect plant height." So there is no mention of roots or leaves,
A is not the answer.
B) amounts of perfume and types of plants.
Yes, we do need the amounts of perfume. However, the question also says types of plants. The background info given says that "They place five identical bean plants in five identical light boxes." So there is no mention of different types of plants.
B is not the answer.
C) dates, perfume distances, and height of plants.
Yes, we do need dates because the info says " they make observations twice a week for one month."
Yes, we do need perfume distances because the info says "perfume at different distances from the plants."
Yes, we do need heights of plants because the info says "if perfume fumes affect plant height."
So C is the answer. But we want to check the last one, just in case.
D) types of perfume, stem colors, and number of flowers.
Yes, we do need types of perfume, but there is no mention of stems (or their colors) nor flowers.
So D is not the answer.
