The inability to concentrate, irritability, a rapid heart rate, and headaches are all signs of
a. stress
b. heart attack
c. decrease in adrenaline
d. all of the above

The correct answer is A.

These are all signs that the person is suffering from stress that is affecting their body physically. Stress has many effects on the body such as those listed, it can also take the form of anger, sadness, irrationality, sleep problems, physical aches and pains in different parts of the body, anxiety and so forth.

to increase speed you need to decrease frictiona dn drag hense why sprinters wear tight track suits to keep tight against there skin to keep away from wind and decrease the amount of drag you are carrying.a swimmer will wear the tightest swim suit they can possibly fit into (i was a size 28 swim suit at meets i wore a   size 23) why? because the tighter your clothing is the less drag and negative force you have. the heavier the clothe the slower and more wind gets caught. cotton tends to hold onto alot of sweat and water making it slower then say a track suit (no idea what they are made of but they are really comfy around your answer )

answer(b) keep oxygenated and deoxygenated blood separate;