Help me with this question please

Only logical answer would be the third one: A temperate forest became a swamp.

Explanation:

A pond cannot become a lake unless human interaction was involved to dig around the pond and fill it in with water, making it a man made lake.

A forest can't become a desert. Come on.

And finally, and arctic region cannot become a tropical region because it would be too cold for trees, grass, animals (other than local animals like killer whales and polar bears) cannot thrive in the region.

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.