The Faint Young Sun Paradox points out the following discrepancy: even though the Early Sun put out significantly less energy/radiation than it does today, the Early Earth was warm enough to support liquid water. What is the most common explanation to resolve this paradox?

Enhanced Green house effect

Explanation:

The paradox describes the  inconsistency between the faint young Sun and the temperate climate  on the early Earth. Despite low radiation by the sun of the early year, the Earth still maintained a temperate climate.

This paradox can be resolved by instigating changes in the atmospheric concentrations of greenhouse gases   like  ammonia (NH3), CH4, or CO2. This is referred to as enhanced green house effect.

the temperature in kelvin of 2.0 dm3 of an ideal gas is doubled and its pressure is increased by a factor of four. what is the final volume of the gas

you can cut your hand off if your not