Organism population size is controlled by different types of limiting factors. The Serengeti Plains are part of the African savanna ecosystem and are home to a variety of different species of plants and animals. The Serengeti Plains experience a seven-month period of seasonal drought each year, during which the ecosystem only receives four inches of rain and the availability of some resources becomes very scarce Which type of limiting factor is the seasonal drought in the Serengeti Plains? a. biotic factor b.abiotic factor c.habitat factor d.competitive factor