Why does an organism’s fitness depend on its environment? (Make it a short sentence and only 2 sentences long)

An organism's fitness depends on its environment because the environment determines the resources available for survival and reproduction, as well as the presence of predators and competitors that can impact its chances of success. The environment also shapes the selection pressures that drive evolution and the adaptation of organisms to their surroundings.

I meant 1 sentence long

An organism's fitness depends on its environment because the environmental conditions determine the challenges and opportunities for survival and reproduction.