Francesco Redi disapproved the theory of spontaneous generation with his experiments. The theory of spontaneous generation states that the living organisms originate from the non-living matter directly. He disapproved this by adding meat in an open container. On the meat, left in open, flies came gathering from the surroundings. These flies laid eggs of the meat. When he covered the container with the net, the flies stayed on the net and laid maggots appeared on the net. But when the container was sealed neither flies or maggot appeared.
Hence, the answer is 'the maggots came from the flies, and the flies came from the surroundings'.
