Intra-specific struggle refers to:

Explanation

Option A is correct. Intra-specific struggle refers to competition between members of the same species. This can include competition for food, water, mates, and territory. Intra-specific struggle is a very important factor in natural selection, as it helps to ensure that only the fittest individuals survive and reproduce. Intra-specific struggle can be very intense, as the individuals involved are all very similar and have the same needs. This can lead to aggression, fighting, and even death. However, intra-specific struggle can also have positive benefits, such as driving innovation and promoting cooperation. The other options are not correct: Competition between members of different species is called interspecific struggle. Environmental struggle is the competition between organisms of a population against one another in nature to maintain themselves in a given environment to survive and reproduce. Prey or predation is the interaction between two species, where one species captures and kills the other for food.