Hot spots, Divergent plate boundaries and Convergent plate boundaries
An area with unifying characteristic is called as a region. The region is a broad geographic area, which is differentiated from other because of the similar features. In a region one or more than one types vegetational climax might be present. It is the continuous and extensive part of the surface. The area in a region is indefinite.
Hence, the given blank can be filled with region.
Answer:
Sometimes, there can be random fluctuations in the numbers of alleles in a population. These changes in relative allele frequency, called genetic drift, can either increase or decrease by chance over time. ... Genetic drift can result in the loss of rare alleles, and can decrease the size of the gene pool.