In 1859 Charles Darwin wrote, "The affinities of all the beings of the same class have sometimes been represented by a great tree As buds give rise by growth to fresh buds, and these if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching and beautiful ramifications." At the base of the evolutionary tree of all life is .

The origin of it.

Explanation:

Its origin refers to the roots from which the tree is held.

A clear example of these words by Charles Darwin is that in the human race, mitochondrial DNA coincides with our ancestors and is something that will never be modified throughout evolution.

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.