Refer to the following graph.
In a laboratory simulation of hydrothermal mineral formation, researchers grew quartz crystals in a hot, water-based fluid. The researchers proposed that a limiting factor would produce an abrupt threshold effect rather than a gradual one. Specifically, they predicted that the drop in the growth-rate gain between the last two 50°C intervals would be at least four times the drop in the growth-rate gain between the first two intervals. The graph’s results are consistent with this proposal, as evidenced by the fact that ____
Which choice most effectively uses data from the graph to complete the text?
For graph-based command-of-evidence questions, translate every part of the claim into a calculation before comparing choices. When a claim concerns changes in interval gains, first find each interval gain, then find the changes between those gains, and finally perform any required ratio comparison.
Hints
Focus on equal intervals
Determine how much the growth rate changes over each consecutive 50°C interval.
Compare the gains
After finding the three interval gains, subtract adjacent gains to determine how much each gain drops.
Test the proposed factor
Divide the later drop by the earlier drop and compare the resulting factor with the threshold in the proposal.
Step-by-step Explanation
Calculate each interval gain
Subtract consecutive growth rates. The three gains are , , and mm/day.
Find the drops between gains
The drop between the first two gains is mm/day. The drop between the last two gains is mm/day.
Compare the drops
The ratio of the later drop to the earlier drop is . Because 6 is greater than 4, the graph is consistent with the proposed abrupt threshold effect.