It was in the primitive oceans that life began almost ___________ billion years back.A 1 B 3.5 C 2.5 D 6

When did life first appear on the planet?3.5 million years ago3.5 billion years ago2.1 million years ago2.1 billion years ago

Chose the correct statement(s)(a) A very thin envelope of gases that surrounded the earth at the time of its formation.(b) About 600 billion years ago plants and animals were formed on the Earth.(c) The two probable sources of oxygen in the atmosphere are photodissociation of watermolecule and evapotranspiration.(d) The evidence of oxygen in the ocean is noted between 2.5 and 3.0 billion years ago.(a) and (b)(b) and (c)(c) and (d)(a) and (d)

During the Precambrian period, the Earth's crust formed, and life_____in the seas. *10 poinfirst appearedthe first to appearthe first appearanceapprearing first

(Q005) The first life formsGroup of answer choicesprobably occurred in oxygen-rich, shallow, warm ocean waters.may have been simple cells of bacteria or archaea living near hydrothermal vents.date back to 4.3 billion years.required oxygen for respiration.

The first thing that was needed on the primitive earth for life to begin wasGroup of answer choicesoxygenorganic moleculescool temperaturessunlightmetabolism