Sunscreen helps because it blocks the sun from your skin
Answer:
Helper T-cells stimulate B-cells to make antibodies and help killer cells develop. Killer T-cells directly kill cells that have already been infected by a foreign invader. T-cells also use cytokines as messenger molecules to send chemical instructions to the rest of the immune system to ramp up its response.
Physical activity is helpful for your heart muscle and also strengthens your immune system also good for your lungs and helps maintain your weight <span />
1) macrophages
2) lymph nodes
3) thymus
4) bone narrow
All work together to make the body function.
