Most people would say that there was never life on Mars, but how can we be sure of that? Scientificly, there is no evidence to show that there was never once life on Mars or if there was.
There actually may have been life on Mars as there is photographic evidence that there was once rivers and lakes there, like earth. But again, as the photographic evidence shows, the lakes, rivers and sources of water have dried up. This makes sense as Mars is a very dry planet. But as I have written, there may have been life on Mars that had become extinct when the sources of water dried up.
On the other hand, there may have never been life on Mars as it is a very hot dry planet and doesn't have any trees which produce oxegen and as you probably know, oxegen is vital for humans as we need it to live. And if there once was life on Mars , how would the life survive as there is no rain to help grow plants that produce food to eat and the animal source of meat that might be there will die because there will be nothing for them to eat.
There are lots of different reasons for both sides of this argument so I need you to comment about what you think.