Darwin's 'Theory of Natural Selection' is mainly based on the following points -
(A) All organisms show a tendency to increase numbers by producing a greater number of off-spring that can survive and reproduce.
(B) The generations continue to modify for adaptation, thereby gradually bringing changes in the species in the future.
(C) The individuals exhibit similarities in their physiological, structural and behavioral traits to bring identical structures.
(D) The number of individuals in a given species remains more or less constant.
Choose the correct answer from the options given below: