For much of the last quarter century, the leading theory of the driving force behind tectonic plate motions envisaged large scale convection currents in the upper mantle, which can be transmitted through the asthenosphere. So letter C. is the Answer.
Natural selection acts for the good of the species. The fittest organisms in a population are those that are strongest, healthiest, fastest, and/or largest. Natural selection is about survival of the very fittest individuals in a population. Natural selection produces organisms perfectly suited to their environments.
The shivering on a cold day is the body's mode of heat generation.This is a negative feedback mechanism where a change is detected by the body'd internal environment and crafts a mechanism to correct it