The following were the main determining factors behind early human behavior. climate change and drought
environmental factors and food supply
glaciers and gathering fruit and nuts
temperature and hunting tools

The answer is- environmental factors and food supply.

Explanation:

d is the correct answer.

b is incorrect because it makes food by itself

c is incorrect because us humans don't know how to produce their own food using the sun like plants.

a is incorrect because consumers can depend on carnivores for eating food for consumers to eat the dead organism. same thing with omnivores.