OK so the answer you are looking for is most likely going to be inter phase because that is what most cells spend their time in.
1. Early earth had no ozone layer, which means it was most likely extremely hot.
2. Young earth had no oxygen and life needs oxygen in order to survive.
3. There where so many natural disasters happening all the time, like volcanic eruptions and constant impact with meteorites and asteroids.
-Extra one (4. Earth originally had no ocean and water. Oceans eventually formed from the water vapor released from the volcanic eruptions, but before that there was nothing.)
The answer is between A and C.
20% is in the great lakes
Molecular biologists are interested in things like the level of gene expression (how much protein or RNA is present at any given time), which molecules are directly touching each other inside the cell, etc. ... Cell biology techniques, on the other hand, want to know what's going on inside intact cells.
( Try to see which one sounds best after reading this)