Question

question 2
fossil fuels and farming chemicals contribute to _____________, which is harmful to human health and causes disease and illness, as well as increases spending on healthcare.
lead exposure
high healthcare costs
air pollution
water quality

Explanation:

Fossil fuels release pollutants like particulate matter, sulfur dioxide, etc. when burned. Farming chemicals (e.g., fertilizers, pesticides) can also release harmful substances into the air (e.g., ammonia from fertilizers). Air pollution is known to cause respiratory diseases (like asthma, COPD), cardiovascular problems, etc. Lead exposure is more related to specific sources like old paint, some industrial processes (not the main contribution from general fossil - fuel burning and farming chemicals in a broad sense). High healthcare costs is a result (as mentioned in the question) but not the direct phenomenon caused. Water quality is more about contamination of water bodies (though some air pollutants can deposit into water, the more direct and main contribution here is air - related).

Answer:

air pollution