AHydrogen
BOxygen
CNitrogen
DCarbon di oxide
Answer:
B. Oxygen
Read Explanation:
Atmospheric composition
Gases, moisture and dust particles are the major constituents. It is the gravitational attraction of the earth that holds the atmosphere close to the earth.
Atmospheric Gases and % of Composition
Nitrogen - 78.08, Oxygen – 20.95, Argon - 0.93, Carbon dioxide - 0.03, Ozone – 0.01 along with Neon, Helium, Krypton, Hydrogen, Xenon are main constituents.
Water reaches the atmosphere through evaporation and causes cloud formation and rain.
Factors influencing the amount of water in the atmosphere:
Rate of evaporation - High at places experiencing higher temperature
Closeness to the surface water sources such as oceans, rivers and other water bodies.
Dust particles are brought to the atmosphere by wind, erupted through volcanic eruption and through formation of ash by burning of meteors.
As the fine dust particles in the atmosphere help in cloud formation they are called as Condensation nuclei.