What stages of the mosquito are considered least mobile, most concentrated, and most accessible?

The correct answer highlights the stages of the mosquito that exhibit certain characteristics, particularly in terms of mobility and accessibility. Pupae and larvae are indeed the least mobile stages of a mosquito's life cycle.

Larvae typically inhabit water bodies, where they move primarily through swimming with minimal displacement, and are often found in very concentrated populations because they depend on stagnant or slow-moving water to thrive. They tend to remain in a small area while feeding on organic material and are quite accessible for control measures.

Pupae, on the other hand, are essentially non-mobile, as they do not swim and are often found resting at the water's surface. This stage serves as a transitional phase to adulthood, making them also easily targeted in terms of mosquito control efforts. These two stages—larvae and pupae—present a consistent opportunity for targeted intervention strategies.

In contrast, the other options either include adults, which have greater mobility, or eggs, which are often laid in various locations and can be less accessible depending on the environmental conditions. Thus, focusing on larvae and pupae results in the identification of the least mobile and most concentrated stages for effective mosquito control.