What is Astrobiology or Exobiology ? What does it deal ?

Explanation

Astrobiology or exobiology, is the science which looks for the presence of extraterrestrial in the universe.
Astrobiology deal with the origin, evolution and distribution of life in universe and to investigate the possibility of life in other worls.
The major concept in astrobiology is the habitable zone. Astrobiology explains that any planets can support the exixtance of life, if it fulfils two criteria :
(i) It must have a right mass to retain an atmosphere.
(i) It must have a right mass to retain an atmosphere.
(ii) It must have an orbit at the right distance from Sun, that it allows liquid water to exist The distance need to be neither too hot nor too cold and is often called Goldilock zone for life.