How do some cold-blooded animals keep their bodies at a constant temperature in cooler environments? by generating their own heat by heating themselves in sunlight by breaking down water and glucose by shivering

I am thinking it is by heating themselves in sunlight. I think this because when I bring lizards to mind, they are cold blooded, and they need sunlight to bath in so they do not start to lack warmth to live.

I hope this helps.

Droughts cause very arid places such as a desert