What do all ecozones have in common

I can see there are no choices, so I'll answer it according to my understanding.

All ecozones have plants and animals.

Explanation:

An "ecozone" (also known as "biogeographic realm") is a bigger ecosystem. This refers to large areas where plants and animals develop over time. It is primarily characterized by the evolutionary history of the "flora" and "fauna."

There are many kinds of ecozones in the world and these are divided into terrestrial and marine types. As a larger type of ecosystem, an ecozone consists of both plants and animals. They portray a biological community where organisms interact with each other and their environment.

So, this explains the answer.