Please help!

The EPA sets national air-quality standards for common air pollutants. The table shows the change in the concentrations of these pollutants over time and the impact on overall air quality. Reducing which pollutant resulted in the most air-quality improvement?

A. CO(carbon monoxide)

B. O3 (ozone)

C. Pb (lead)

D. NO2 (nitrite)

that is true   : ) hope this you

it's c.us forest service

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .

the circled areas are referred to   as sunspots.   the sunspots are cooler than the   surrounding area.

sunspots are temporary phenomena on the photosphere of the sun that appear visibly as dark spots compared to surrounding regions. they correspond to concentrations of magnetic field flux that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere.