SOLAR SYSTEM

Detailed explanation-1: -Why do scientists study the characteristics that make life on Earth possible? To know what life supporting conditions to look for on other planets.

Detailed explanation-2: -It is useful to categorize the requirements for life on Earth as four items: energy, carbon, liquid water, and various other elements.

Detailed explanation-3: -Earth is unique in the Solar System as being the only planet that is able to support life in all its forms: from basic living micro-organisms to highly sophisticated and intelligent human beings.

Detailed explanation-4: -The simultaneous detection of water, carbon dioxide, and oxygen or ozone would be a strong indicator that biological processes are occurring on a planet.

Detailed explanation-5: -If the inside of the planet is hot enough, liquid water beneath ice or the ground may be possible. Larger planets are more likely to be habitable than smaller ones because they have enough gravity to hold onto an atmosphere and because they are more likely to be tectonically active.