资料题：According to the 8econd paragraph, it is obvious that the earth（　）。

The gold ball you see in the sky is our sun.Our sun is really a star.It is just like the ones you see at right.We can't see the other stars when the sun is out.That's because our star gives of so much light.Our sun isn't the biggest star.But it is the closest.So to us, it looks bigger and lighter than the other stars.We live on the earth.It does not stay sill.It is always turning.When the part of the earth we live on is facing the sun, we have day.When the part of the earth we live on is not facing the sun, we have night.So the sun gives us day and night.The light from the sun helps us in other ways, too.Plants use the light to make food.This helps them grow.Then animals eat the plants.People can eat the plants and the animals.So our sun helps us get our food.The sun, like all stars, is a big ball of fire.It is very hot.So it keeps the earth from getting too cold.If it weren't for the sun, the earth would be a big ball of ice.The sun does many good things for us.But it can hurt us, too.Doctors tell us that we  should not stay out in the sun too long.And we should never look right at it.ht can hurt our eyes.