what does snail eat
It depends on the type of snails. Garden snails usually eat plant material like beans, lettuce and tomatoes. Some land snails like eating fungus more than plants, and some like eating almost anything dead and rotting. Many of the marine snails are carnivores and eat worms, small fish, small crabs, or other snails.
So it could be seen that Roman snails do feed on parsley, but only in spring, not in the rest of the year. Basil will be eaten by snails also only part of the year. Concerning wild plants the feeding behaviour of snails can also be very different. Clover is a favourite snail food, but dandelion is not.