下列句子中哪些是定语从句
1.People who eat a balanced diet should be healthier than those who only eat biscuits and hamburgers,shouldn’t they?
2.I’ve heard eating burnt food like this can increase the risk of cancer.
3.And I think most people are in agreement that fruit and vegetables are good for health.
4.Actually,don’t you know that it’s been found in laboratory testing that some types of oil are really bad for us?
5.Still,it’s a great place to visit
6.There’s just so much to see and do here