Question

Which of the following statements are correct with respect to origin of earth?
a. There was no atmosphere on early earth.
b. Water vapour, methane, carbon dioxide and ammonia were released from molten mass which covered the earth.
c. Oxygen gas was released from plants during photosynthesis.

• A. Statements ‘a’ and ‘b’ are correct
• B. All statements are correct
• C. Statements ‘b’ and ‘c’ are correct
• D. Statements ‘a’ and ‘c’ are correct

Answer 1

The correct option is A Statements ‘a’ and ‘b’ are correct

Earth was formed approximately 4.5 billion years ago. As it cooled down, a primitive atmosphere was created by the outgassing of early volcanoes. The early atmosphere contained no oxygen and could not support most of the life forms. In addition to the molten lava flowing into the ocean, some of the chemicals viz., hydrogen, helium, carbon dioxide, methane, ammonia etc. were supposedly washed down by the rains into the oceans where these chemicals gradually converted to simple organic molecules that eventually joined together into complex organic molecules. Oxygen and hydrogen gases were formed by splitting of water by UV rays.