Scientists explain that life arose from non-life billions of years ago through the theory of abiogenesis. Could life arise from non-life today?

Because light travels in a straight line and casts a shadow, isaac newton hypothesized that light is

Amichelson interferometer operating at a 600 nm wavelength has a 3.02-cm-long glass cell in one arm. to begin, the air is pumped out of the cell and mirror m2 is adjusted to produce a bright spot at the center of the interference pattern. then a valve is opened and air is slowly admitted into the cell. the index of refraction of air at 1.00 atm pressure is 1.00028.how many bright-dark-bright fringe shifts are observed as the cell fills with air?

When using the scientist method, which step comes last?