hard · Act science

Two scientists debate why a lake's dissolved oxygen (DO) drops sharply each August. Scientist 1: The drop is caused by warming. Warmer water holds less dissolved gas, so as surface temperature peaks in August, DO must fall. Scientist 2: The drop is caused by bacterial decay. Algae that bloom in midsummer die and sink, and bacteria consume oxygen as they decompose them; temperature is only incidental. Measurements show that in one unusually cool August, surface temperature stayed low yet DO still fell to its typical August minimum, while bottom-water ammonia (a decay product) spiked. Which statement is true?

1. The cool-August result weakens Scientist 1's view and supports Scientist 2's view.
2. The cool-August result supports Scientist 1's view and weakens Scientist 2's view.
3. The cool-August result is consistent with both views equally.
4. The cool-August result weakens both views.

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