According to current understanding, key requirement/s for life is/are: 

What do we conclude if a planet has few impact craters of any size? 

Which of the below are properties that life does not possess? 

Fossil evidence suggests that life on Earth arose 

Why are hydrothermal vents considered a possible location for the origin of early life? 

To determine a planet’s average density, we can use 

What is the reason for the fact that we look back in time when observing distant objects? 

What shape will the galaxy resulting from the impending collision between Andromeda and Milky Way most likely have? 

What is the shape of the Milky Way’s halo? 

Why can't we see the structures in the centre of our Galaxy with optical telescopes?