The correct answer is option (A) competition.
Competition refers to the type of interaction between the species or the organims in which both are harmed. In the above example of tadpoles grown in high-tadpole-density ponds showed decreased survival and growth rates of tadpoles than the tadpoles in lower-tadpole-density pond because of the competition existing between the species of the tadpole in the pond. This type of competition among the same species is called the intraspecific competition. When the number of species of tadpoles are more, it limits the availability of resources like the food, light, space, water and mates. This results in intraspecific competition and the number of tadpoles tend to decrease.
