√√∛∛∛Which events contributed to life evolving on Earth? Check all that apply.

Organisms began to photosynthesize.
The surface cooled, and water condensed.
Volcanoes added carbon dioxide to the atmosphere.
Ozone formed and blocked ultraviolet rays from the Sun.
Comets crashed into Earth, releasing water.

A0.10 m aqueous solution of sodium sulfate is a better conductor of electricity than a 0.10 m aqueous solution of sodium chloride. which of the following best explains this observation? (a) sodium sulfate is more soluble in water than sodium chloride. (b) sodium sulfate has a higher molar mass than sodium chloride. (c) to prepare a given volume of 0.10 m solution, the mass of sodium sulfate needed is more than twice the mass of sodium chloride needed. (d) more moles of ions are present in a given volume of 0.10 m sodium sulfate than in the same volume of 0.10 m sodium chloride. (e) the degree of dissociation of sodium sulfate in solution is significantly greater than that of sodium chloride.