How does the Earth's position in Space, mass and atmosphere allow the planet to support life?

The position is the orbit around the sun. If the earth would move x% it would be either too cold or too hot for life to ever develop.

The mass is very important because of the amount of heat the planet has to offer with its size. As well as volcanic activity and tectonic plate shifting.

The atomsphere contains all the gasses vital for life such as oxygen, nitrogen and carbondioxide

The fact that Earth has plate tectonics allows for the carbon-silicate cycle to operate over geological timescales," Valencia said. "With the carbon-silicate cycle, the levels of carbon in the atmosphere get regulated to keep the surface temperature around that of liquid water."

Plate tectonics and water are inextricably linked. Not only does plate tectonics enable liquid water to exist by way of regulating the temperature, but many scientists have argued water enables plate tectonics to happen.