Which explanation is most likely the reason for the evolution of a larger brain in humans?
the size of the human brain increases the more it is used.
a larger brain allows humans to solve complex problems.
the size of the human brain has changed randomly over time due to mutations.
a large brain increases humans’ ability to fight and survive disease.

The correct statement is A larger brain allows humans to solve complex problems.

Explanation:

From the ancient time, the human brain has size increased three times. The most probable reason for the evolution of brains is that larger brain allows humans to handle complex problems more easily.

complex and large brains help humans to understand and store a different type of knowledge and information and aids in interacting with each other.  

The current time human has a larger and complex brain in any living primates.

Thus, the correct statement is A larger brain allows humans to solve complex problems.

false because ozone (o3) depletion does not cause global warming, but both of these environmental problems have a common cause: human activities that release pollutants into the atmosphere altering it.

global warming is caused primarily by putting too much carbon dioxide into the atmosphere when coal, oil, and natural gas are burned to generate electricity or to run our cars.

explanation:

well, i believe that the answer is 2. : 3