The correct answer is - A. A few centimeters a year.
Earth's crustal plates move very slowly, between 2 cm and 5 cm (depending on the plate) annually. This is the reason why it takes millions of years for them to significantly change their position, and with it the appearance of our planet. These crustal plates are slowly moving around the planet because they are powered by flow in the interior mantle.
A chemical reaction which is associated with a release of energy and thus, is associated with a negative free energy change is said to be an exergonic reaction.
An exergonic reaction owing to the negative free energy change is a spontaneous reaction.
The energy that is released in the exergonic reaction is usually observed in the form of heat and light.
The energy is released due to the breaking of the chemical bonds.
Therefore, on burning of the firewood the bonds between the glucose molecules break up which leads to the release of energy in the form of heat and light and this is thus, an example of an exergonic reaction.
