What was the control in Redi's experiment? A. Meat covered by jars that didn't have contact with air B. A straight neck flask to allow air to get in C. Uncovered meat that had contact with air D. A swan neck flask that prevented air from getting in

The correct answer is option C. "Uncovered meat that had contact with air".

Explanation:

In 1668, the Italian scientist Francesco Redi performed a celebrated experiment to prove that maggots are not spontaneously created by placing fresh meat in each of two different jars: one opened and one covered with a cloth. Redi used an uncovered meat that had contact with air as a control, expecting that flies will come in and the maggots will be developed as they do in nature.