How and why does a decrease in ambient temperature affect the vital activity of gastropods?

Gastropods or snails are cold-blooded animals. Different types of snails have adapted to live in different habitats: in the seas and oceans, fresh water bodies and on land. They cannot keep their body temperature constant. Their livelihoods directly depend on the ambient temperature. When the temperature drops, they become lethargic, stop eating and hibernate. When the ambient temperature becomes optimal for life, the snail wakes up. This helps organisms not to die under adverse conditions and lack of nutrition.