Answer:
The correct option is;
Darwin's theory of natural selection
Step-by-step explanation:
(A) The theory of gravity was introduced Sir Isaac Newton in the published work of Philosophiae Naturalis Principia Mathematica which consisted of three books on the 5th of July 1687
(B) In 1839, and 1858, Theodor Schwann and Rudolf Virchow, respectively proposed the cell theory which consisted three parts viz
1) Cells are the building blocks of organisms
2) The cell is the fundamental life unit
3) Cells come from other preexisting cells
The first two parts was proposed by Theodor Schwann in 1839, while the third part was proposed by Rudolf Virchow, in 1858
(C) In 1859, Charles Darwin proposed the theory of natural selection in his book the "On the Origin of Species" which is the process by which an organism change so as to survive ad reproduce in its environment
(D) In 1912, Alfred Wegener, proposed the theory of continental drift.