Suppose the environment of a desert ecosystem changes to become much colder and wetter. Which organisms in this ecosystem will most likely be affected

All the organisms which will be present in the ecosystem will be affected.

Explanation:

A change in the temperature or weather will affect all the organisms of an ecosystem. The plants of the desert are adapted to live in hot conditions. When it becomes colder and wetter, the plants may not be able to adapt to the changes or they might wilt.

Similarly, the animals in the desert are adapted to survive in hot conditions. They will not have best adaptations to survive in cooler weather and hence, the whole ecosystem will be affected.