Question

how has climate change impacted the spread of vector - borne diseases?
multiple choice
as ice melts, novel bacteria and viruses are released resulting in more infections.
as temperatures have warmed, disease vectors like mosquitos and ticks, have increased their range
diseases spread more easily in warmer, drier conditions.
as habitats are altered, humans encounter more animals leading to greater frequency of disease transmission.

Explanation:

Vector - borne diseases are transmitted by vectors like mosquitoes and ticks. Climate change (specifically temperature rise) allows these vectors to expand their geographical range. For example, mosquitoes that carry diseases such as malaria or Zika virus can now survive in areas that were previously too cold for them. This expansion of their range leads to a greater potential for human exposure to these disease - carrying vectors.
The first option about ice - melt releasing novel bacteria and viruses is more related to the release of ancient pathogens rather than vector - borne diseases. The third option is incorrect as many vector - borne diseases (like those carried by mosquitoes) thrive in warmer and more humid (not drier) conditions. The fourth option is about general habitat - related disease transmission (not specifically vector - borne).

Answer:

As temperatures have warmed, disease vectors like mosquitos and ticks, have increased their range.