Explain how you use pairs of muscles to flex and extend you arm.

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.

When diving into water, it is important to look before diving to avoid that could damage your nervous system deep water underwater hazards living creatures water toys

Explain what causes the skin to burn in the sun? explain why people should avoid the sun if taking a photosensitive medication?