3. Life exists in extreme conditions
Just because Earth has air, water, and a few other materials, does not mean everywhere in the planet the conditions are the same. There are parts of the Earth where the living conditions are extremely poor. Even in those extreme conditions, life has managed to find a way and exists. We are talking about the bottom of the ocean where the sunlight does not reach. We are talking about hundreds of feet deep buried in the glaciers. A lot of life forms have been discovered from these places. So what makes you think life cannot be formed in other planets where the conditions might be tougher or be extreme?