The theory of tectonic plates explains that large convectional currents occuring in the mantle(as a result of magma) are the reasons plates,and so continents,are moved. Note movement occurs in the boundary in between the plates.
Females have two X chromosomes while males have one X and one Y chromosome
When a lineage splits into multiple line of descents, then, it leads to speciation. It is a process by which a single population evolves into different species. The process of speciation leads to the development of two or more species as the lineages are splitted. These two evolved species are genetically independent.
Hence, the blank can be filled with 'speciation'.
