1.   Could life originate in environments where there is no oxygen?

2.   But traces of earliest life are scant, leaving scientists at a loss to explain how life originated or when it began evolving into complex forms.

3.   Dr. Cyril Ponnamperuma, a chemist who explored the chemical paths by which life might have originated, died Tuesday at Washington Adventist Hospital.

4.   How did life originate?

5.   How did life originate on Earth?

6.   In the past, the toughest part of the Drake Equation was thought to be estimating the fraction of planets on which life originates.

7.   Miller has contended over the years that life probably originated on the earth itself, without help from the depths of space.

8.   Not all scientists believe that life originated on earth.

9.   No one has yet shown how life originated on Earth, and the chance that science will ever unlock all the details of the process seems vanishingly small.

10.   Ponnamperuma also took seriously the proposal that life may have originated in the superheated vents on the deep sea floor.