The health effects of toxic substances and hazardous wastes are not yet fully understood. research to better understand how these exposures may impact health is ongoing. meanwhile, efforts to reduce exposures continue. reducing exposure to toxic substances and hazardous wastes is fundamental to environmental health. one way you can reduce toxins in the environment is to

d reduce combustion.

or b batteries recycling them

beacause limiting water use isnt going  to  reduce toxins

D) reduce or eliminate combustion of any kind to improve air quality.

Explanation:

Pollutants from combustion are gases or particles such as carbon monoxide and nitrogen dioxide and are related to cases with the way in which internal spaces are heated. They originate from the materials that are burned, heaters, wood and gas stoves, ovens, and water heaters along with fireplaces. Decreasing this type of pollutants would greatly improve air quality.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.