Final answer:
The plant that does best at 70°F would likely have an optimal temperature slightly above 20°C but not so high as to negatively impact growth due to increased respiration costs. No further details on Plants A, B, C, and D's temperature preferences are provided to make a conclusive determination.
Step-by-step explanation:
The question pertains to identifying which plant would thrive the best at a constant temperature of about 70°F. Based on the provided information, plants have an optimal temperature for growth, which varies across species. Most plants increase their activities and growth within the temperature range of 0 to 20°C (32 to 68°F). Growth diminishes with temperatures above their optimal range due to increased respiration over photosynthesis. Since 70°F is approximately 21°C, we can infer the plant that would do best is one that has an optimal temperature slightly above 20°C, but not as high as to favor increased respiration that would inhibit growth.
Plants adapted to cooler temperatures, such as those that thrive well below 35°C, and those that are drought-resistant and require less water at higher temperatures, could be potential candidates. However, no specifics are given for Plants A, B, C, and D, regarding their temperature preferences, rendering it difficult to make a conclusive determination based solely on this data.