Which of the following environmental factors can affect the size of a population?

The correct answer is: All of the above

• Predators, disease, and food supply are some of the environmental factors that limit the growth of the population.
•  Predators play an important role to limit the number of herbivores in an area. 
• If the population begins to grow, food supply plays an important role. Shortage of food supply is seen in the areas with abundant population, thus little of the population gets to eat.
• An epidemic also plays an important role in controlling the size of the population