Answer:
Four major components
Step-by-step explanation:
A- There are 4 major components of the blood.
1- Red Blood cells 45% of blood portion
2- White blood cells make up to 1% of blood proportion
3- Platelets less than 1% of the blood portion
4- Plasma 55% of the blood components
B- platelets are responsible for initiating the clotting process.
C- pathogens can enter into the body through airborne particles, skin contact, through food and body fluids.