How can mutagens cause mutations despite the body's DNA repair enzymes?

The efficiency of the repair mechanism is not 100 percent.

Explanation:

The DNA damages caused by physical conditions (i.e., exposure to radiation, UV light, etc.) and chemical agents (i.e., mutagenic compounds) are regularly repaired by DNA repair enzymes that recognize and correct nucleotide errors before the fixation of the mutation. The Apurinic/apyrimidinic (AP) endonuclease is the enzyme responsible for repairing the damaged DNA. However, this process is not perfect, and mutations that were not recognized by this mechanism are fixed in the next round of replication.

as resources become scarce because of population growth, the growth decreases after few years due to lack of resources and food.

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.