Components of Blood

All blood contains the same basic components:

• red blood cells that deliver oxygen
• white blood cells that fight infections
• platelets that help blood clot
• plasma, the liquid part of blood

The two main blood groups are ABO and Rh.

The ABO blood system has four main types:

• Type A: This blood type has a marker known as A.
• Type B: This blood type has a marker known as B.
• Type AB: This blood type has both A and B markers.
• Type O: This blood type has neither A nor B markers.

Blood is further classified as being either "Rh positive" (meaning it has Rh factor) or "Rh negative" (without Rh factor).

So, there are eight possible blood types:

1. O negative. This blood type doesn't have A or B markers, and it doesn't have Rh factor.
2. O positive. This blood type doesn't have A or B markers, but it does have Rh factor. O positive blood is one of the two most common blood types (the other being A positive).
3. A negative. This blood type has A marker only.
4. A positive. This blood type has A marker and Rh factor, but not B marker. Along with O positive, it's one of the two most common blood types.
5. B negative. This blood type has B marker only.
6. B positive. This blood type has B marker and Rh factor, but not A marker.
7. AB negative. This blood type has A and B markers, but not Rh factor.
8. AB positive. This blood type has all three types of markers — A, B, and Rh factor.

References :

https://kidshealth.org/en/teens/blood-types.html#:~:text=Categorizing%20blood%20according%20to%20type,cells%20as%20belonging%20in%20us.