When did life begin?

Answer 1

At least #3.8# billion years ago.

The earliest direct evidence we have of life on Earth is about #3.8# billion years old. We also have rocks dating back #4# billion years with inclusions as old as #4.4# billion years, but the evidence of life in these samples is circumstantial and may have other causes.

There is speculation as to whether life began outside our solar system and seeded life here. In particular the Panspermia theory is that life is everywhere in the Universe, having begun shortly after the Big Bang #13.8# billion years ago, seeded into our solar system in the form of extremophiles (small organisms that survive harsh conditions).

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Answer 2

Levi Alexander

Although the precise beginning of life is unknown, evidence points to the possibility that simple life forms first emerged some 3.5 billion years ago.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.