Pharmaceutical companies are required by the FDA to conduct studies measuring drug efficacy by using informed human subjects that are randomly assigned to either a group that receives the drug being investigated or a group receiving a placebo. These studies are referred to as .

Clinical studies

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.