In order for photosynthesis to take place what must be present?
1. Sunlight
2. Oxgyen

Sunlight

Explanation:

Cuz plants need sunlight for photosynthesis but plants throw out oxygen

significant amounts of nitrogen oxides, carbon monoxide, and other pollution

explanation:

passenger vehicles are a major pollution contributor, producing significant amounts of nitrogen oxides, carbon monoxide, and other pollution. in 2013, transportation contributed more than half of the carbon monoxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into our air.