What form of struggle for existence is the most intense and why?

Darwin considered the intraspecific struggle the most intense. In individuals of the same species, the requirements for food, territory and other conditions of existence are the same. Therefore, competition between them is especially acute.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.