The common component of air pollution is particulate matter (PM). This is a complex mixture of extremely small particles and liquid droplets.
The major components of PM are sulphates, nitrates, ammonia, sodium chloride, black carbon, dust particles and water. PM comes from dust , soot, smoke, industry and vehicle exhaust as well as complex chemical reactions with other pollutants.
Burning of fossil fuels produces sulphur dioxide . It is a colorless gas that pollutes the air and can cause health problems affecting the respiratory system.
Embryonic development involves process of formation and development of an embryo. In humans, during the early stages, 10 weeks of embryonic development, all the major body organs are formed.
the <em>sun's corona</em> is only visable when there is a solar eclipse
