Which of the following activities constitutes biological control?

The activity that constitutes biological control is Tilapia feeding on the larvae and pupae of mosquito. Biological control is a method of managing pests, diseases or weeds using natural enemies, such as predators, parasites, and pathogens. In this case, Tilapia is a natural predator of mosquito larvae and pupae. By feeding on the mosquito larvae and pupae, Tilapia helps to control the mosquito population and reduce the risk of mosquito-borne diseases like malaria, dengue fever, and Zika virus. This method is environmentally friendly and sustainable compared to the use of chemical pesticides, which can have harmful effects on non-target organisms and the ecosystem. The other activities mentioned do not fall under biological control as they do not involve the use of natural enemies to manage pests.