If we are all out of africa why are there so many different skin colors answers

How do earth’s systems interact with each other?

The double-blind procedure is most for a.random assignment b.the placebo effect c.operational definitions replication d. standard deviations

The use of fertilizer on a large farm would have the largest effect on which of the following? rate of photosynthesis in local plants amount of smog in the lower atmosphere rate of anaerobic respiration in aquatic bacteria extent of eutrophication in nearby water bodies rate of evapotranspiration from surrounding area