Which of the following aids the immune system in fighting infections?
a. plasma
b. platelets
c. red blood cells
d. white blood cells

Which of the following can refer to the form of exercises that uses free weights, weight machines. resistance bands, or the weight of the body to put stress on the muscles ? (a) strength training(b)weight training(c)resistance training(d) all the above

Ireally need to know this answer asap

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