Resting heart rate, exercise heart rate, and activity

Which statement is true about common childhood infectious disease? a. children should always be given antibiotics to treat an infectious illness. b. frequency of infectious illnesses usually increases as children grow older. c. having a minor infectious illness weakens a child's immune system. d. infectious illnesses are usually mild and require no medication.

Brian said that when you get your body broken such as a arm or leg. it means your bones break to pieces and must do surgery or get a cast to fix it.is it true or false?

How could natural selection best be used to explain the evolution of the white fur of arctic fox