Question 16·Easy·Command of Evidence
To investigate how sunlight affects plant growth, a horticulture student grew identical seedlings under different amounts of sunlight per day. After three weeks, the student recorded the average height (in centimeters) of the seedlings at each sunlight level. The graph shows the results.
Based on the graph, the student claims that increasing sunlight from 2 hours per day to 6 hours per day increased the average seedling height by about 5 centimeters.
Which choice most effectively uses data from the graph to justify the underlined claim?
For graph-based command-of-evidence questions, identify the exact quantities and categories named in the claim (here, heights at 2 and 6 hours). Read those values from the graph, compute the stated relationship (difference, increase, decrease, etc.), and select the option that cites the same two data points and matches the relationship.
Hints
Use the two sunlight levels named in the claim
The claim is about 2 hours per day and 6 hours per day, so find those two points on the graph first.
Read the approximate heights at those points
Estimate the average height at 2 hours and at 6 hours from the vertical axis.
Check that the difference matches the claim
Subtract the 2-hour height from the 6-hour height and look for an option stating a difference of about 5 cm.
Step-by-step Explanation
Focus on what the claim measures
The claim is about the change in average height when sunlight increases specifically from 2 hours to 6 hours per day.
Read the two values from the graph
From the graph, the average height is about 7 cm at 2 hours of sunlight and about 12 cm at 6 hours of sunlight.
Choose the option that matches those values and the stated increase
The statement that uses 7 cm (2 hours) and 12 cm (6 hours) and notes the increase is about 5 cm is correct: The average height was about 7 cm at 2 hours and about 12 cm at 6 hours, an increase of about 5 cm.