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.

A large brain allows humans to solve complex problems. This, in turn, has allowed humans with bigger brains to survive better than humans with smaller brains.

1. true.2. true.3. true.4. false.5. true.the concept of darwin's theory of evolution involves the idea that there are limited resources in a given living environment and that the organisms which live within have variations in their genetic make up due to random mating. the ones with beneficial genetic variations can express certain traits which give them an upper hand in surviving and reproducing in the said environment compared to ones who may have a more disadvantageous variation in traits. over time, the organisms with an upper hand will survive and reproduce more frequently and pass on their beneficial genes while the others die. the result is evolution, where we observe (usually, but not always) eventually, phenotypic distinct changes.