How and why does scientist care about the benefits of separating mixtures?

Which action is characterized of mental illness 1.brushing teeth every hour because ones mouth feels dirty ? 2. forgetting to eat breakfast on a busy day? 3.crying three days over a relationship breakup? 4.feeling embarrassed about going to school after failing in front of friends?

Why is it important to know first aid/ cpr/ aed?

Which of the following statements concerning cancer and mutations is correct? a: cancer can only occur with a mutation in a somatic cell. b: usually, multiple mutations are required in different genes to cause cancer. c: none of the other answer options is correct. d: cancer can only occur with a mutation in a germ cell. e: usually, a single mutation is all that is required to cause cancer.