question_answer 27)

  The two forms of oxygen found in the atmosphere are (a) water and ozone        (b) water and oxygen   (c) ozone and oxygen     (d) water and carbon-dioxide

Answer:

  (c) Oxygen is present in our atmosphere in the form of a diatomic molecule. It is present in troposphere in approx mistily 20.93 (percentage of volume). Oxygen is required by all the living beings for respiration and burning (combustion) of materials. Its percentage in air is balanced by photosynthesis. Ozone is an allotrope of oxygen present in significant amount in stratosphere. It is a diatomic blue gas with pungent condor. The ozone is highly important as it filter out high energy UV radiations from the sun. These radiations split ozone into molecular and atomic oxygen.