Why was the importance of water vapour in the secondary atmosphere not limited only to atmosphere?

Correct answer: Because it later produced rainfall and hydrosphere

The direct answer is A, because water vapour later produced rainfall and the hydrosphere. A secondary atmosphere contained large amounts of water vapour released from Earth’s hot interior and volcanic activity. As the surface gradually cooled, the vapour condensed into liquid water. Clouds and rainfall formed, and water collected in low areas to create oceans and other parts of the hydrosphere. Thus water vapour affected not only the air but also Earth’s surface and water system. B is wrong because the core formed through separation of materials inside Earth, not from atmospheric water vapour. C is wrong because water vapour did not immediately break the crust; cooling actually helped the surface become stable. D is wrong because solar wind comes from the Sun, not from Earth’s water vapour. A correctly shows the atmosphere-to-hydrosphere link. Memory cue: cooling vapour condenses, rains and fills basins.