Why Neptune is the coldest planet

Because it's the farthest planet away from the sun.

Explanation:

Neptune is the coldest planet because it is the eighth planet in our solar system and therefore the furthest away from the Sun. ... Neptune lacks a solid surface as such and instead has an icy water layer that serves as the planet's mantle

answer; /// i believe that one of the causes is (a loss of habitat);

the answer is a i had that before