Struggle for existence and survival of the fittest theories were proposed by ________

The correct option is A Darwin

Struggle for existence and survival of the fittest theories were proposed by Darwin. The essence of Darwinian theory about evolution is Natural selection. The concept says that nature selects for fitness. This fitness is based on characteristics which are inherited.

Hence some organisations are better adopted to survive is an otherwise hostile environment. Adaptive ability is inherited and it has a genetic basis. Fitness is the end result of the ability to adopt and get selected by nature. Branching descent and Natural selection are two key concepts of Darwinian Theory of Evolution.