The spread of infectious diseases is expected to increase with climate change, mainly because:

• A. warmer temperatures expand the habitats of disease-carrying vectors such as mosquitoes
• B. higher carbon dioxide levels kill beneficial microbes in the soil
• C. climate change causes all bacteria to become antibiotic resistant
• D. climate change directly increases the mutation rate of all pathogens

Answer: (A)

Verified step by step guidance

1. Identify the key concept: how climate change influences the spread of infectious diseases, focusing on the role of environmental factors.
2. Understand that many infectious diseases are transmitted by vectors, such as mosquitoes, ticks, and other organisms that carry pathogens from one host to another.
3. Recognize that warmer temperatures caused by climate change can expand the geographical range and breeding seasons of these vectors, allowing them to survive and thrive in new areas.
4. Evaluate the other options: higher CO2 levels affecting soil microbes, climate change causing universal antibiotic resistance, and direct increases in mutation rates are less supported or incorrect mechanisms in this context.
5. Conclude that the most scientifically supported reason is that warmer temperatures expand the habitats of disease-carrying vectors, thereby increasing the potential for disease spread.