Question

botanists are biologists who specialize in studying plants. what is the best method a botanist could use to study the effect of air pollution on the growth rate of corn plants?

• conduct a controlled experiment, exposing some corn plants to pollution and others to clean air
• measure the height of corn plants on a clear day and again on a day when pollution is high
• survey farmers for their opinion about the effect of pollution on the growth rate of corn
• compare the growth rate of corn plants in a polluted area to the growth rate of other types of plants in the area

Explanation:

To study the effect of air pollution on corn growth rate, a controlled experiment is best. In a controlled experiment, variables (like pollution) are manipulated while others are kept constant. Exposing some corn to pollution and others to clean air isolates the pollution variable, allowing a clear comparison of growth rates. Measuring height on different days (option 2) doesn't isolate pollution. Surveying farmers (option 3) gives opinions, not scientific data. Comparing corn to other plants (option 4) doesn't focus on pollution's effect on corn.

Answer:

A. conduct a controlled experiment, exposing some corn plants to pollution and others to clean air