Which two factors could lead to the evolution of a species over time?

There are four forces of evolution: mutation, gene flow, genetic drift, and natural selection. Mutation creates new genetic variation in a gene pool. Gene flow and genetic drift alter allele frequencies in a gene pool.

Explanation:

answer: grassland biomes are closer to the equator and receive more rain.

grasslands are biomes that are dominated by grasses rather shrubs and trees. savanna are biomes that exhibit grasses, shrubs and small tree as vegetation. grasslands are located near the equator of the earth. these are found in north america. savanna biomes are found in africa, south america, australia and india. grassland exhibit moderate climatic conditions, it receives   amount of rainfall higher than savanna.   therefore, savanna exhibit dry and hot climatic conditions.