Which biomes would be found nearest to the equator?What is the difference between the grassland and savanna biomes?

Tropical rainforests are found closer to the equator where it is warm. Grasslands and savannas are related and often intermixed biomes typically dominated by grasses. True grassland supporters few if any would you plans, while savannas  included varying proportions of shrubs and trees, grading into woodland where canopies begin mingling.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."