EVERYDAY SCIENCE

Detailed explanation-1: -Explanation: During the early Archean Eon the free Oxygen was found to be absent. Though water molecules were found and the water molecules contained Oxygen it was found combined with the Hydrogen molecule not as free Oxygen. Due to the absence of Oxygen only blue green algae was found.

Detailed explanation-2: -The Archean Eon (4 to 2.5 billion years ago) There was no oxygen gas on Earth. Oxygen was only in compounds such as water. Complex chemical reactions in the young oceans transformed carbon-containing molecules into simple, living cells that did not need oxygen to live.

Detailed explanation-3: -Earth’s original atmosphere was rich in methane, ammonia, water vapour, and the noble gas neon, but it lacked free oxygen.

Detailed explanation-4: -Radon is a radioactive element and is not found in the atmosphere.

Detailed explanation-5: -The atmosphere was very different from what we breathe today; at that time, it was likely a reducing atmosphere of methane, ammonia, and other gases which would be toxic to most life on our planet today. Also during this time, the Earth’s crust cooled enough that rocks and continental plates began to form.