Final answer:
D. Warm and humid. Warm and humid conditions are most conducive for flea development, similar to the favorable environment for mosquito reproduction, but very hot and dry conditions would lead to a decrease in mosquito populations.
Step-by-step explanation:
The weather condition that is highly conducive to flea development is Warm and humid environments. Fleas thrive in these conditions because the warmth facilitates rapid development while the humidity is necessary for their eggs to hatch. Similar factors affect mosquito populations. According to the data summarized from research conducted in Brazil, mosquito populations would decrease in very hot (above 30°C) and very dry (below 60% humidity) conditions as these are close to the limit for producing viable offspring. Less than 60% humidity is not conducive for offspring production for mosquitos and resulting in a population decrease. It is important to apply this understanding regarding weather conditions and their effect on insect populations to control and manage these pests effectively.