Conditions for life on earth

Ooh, I don't know the "correct" answers prescribed by your qualification or exam board, but from a science point of view this is what I think:- Distance from the Sun - the Earth exists in the so-called "Goldilocks Zone" in terms of distance from our star, where it isn't so hot that all the water on the planet evaporates (water is essential for life as we know it), and it isn't so cold that the essential metabolic processes done by enzymes cannot function. - Tilted axis - I'm not sure about this one, perhaps another tutor or student can enlighten us? The tilted axis enables different seasons in each hemisphere (it is currently Spring time in South Africa, whereas it is Autumn in the UK). I would predict it's so that there are zones on the planet where seasons stop those areas becoming either parched (such as deserts at the equator) or freezing cold (such as at the poles), which enables different forms of life to live... All this is just speculation though!- Mass of the planet - this one is more straightforward. Why is there no liquid water on mars? Because it is too small. The more massive an object is the more gravity it has, therefore if you went to visit Jupiter its gravity would crush you, but you get that amazing "bouncy" step when hanging out on the moon where gravity is about a tenth that on Earth. Without water there cannot be life (as we know it), and therefore Mars's low gravity which allowed any water that used to exist on it to evaporate into space, means there is very, very, very little chance us ever finding extant (still living) life on Mars.- Magnetic field - this has to do with solar radiation. The Sun obviously gives us light, but it also gives off ultraviolet radiation and other damaging types of electromagnetic radiation. Because of the Earth's magnetic field, some of this harmful radiation is deflected. Much like a shield, it protects us from certain types of radiation that would otherwise kill living organisms.- Day length - this one again I am not sure of, but the other three I think I've answered, at least in brief and from my general science understanding. I hope that it helps, and that you get answers for the other questions you seek!

Awesome stuff! 

Thanks!! This helped a lot