blood is B plus and 0 how can the son be D RH negative?

The given scenario is not possible because the son cannot have a D RH negative blood type if both parents have B+ and O blood types.

A person's blood type is determined by the combination of antigens (proteins) on the surface of their red blood cells and the corresponding antibodies in their plasma. The ABO blood group system has four main blood types: A, B, AB, and O. The Rh (Rhesus) factor is another antigen that can be present on red blood cells, resulting in Rh-positive (Rh+) or Rh-negative (Rh-) blood types.

In this case, the mother has blood type B+ (B positive), which means she has both the B antigen on her red blood cells and the Rh factor (D antigen). The father has blood type 0 (O positive), which means he has neither the A nor B antigen on his red blood cells but does have the Rh factor.

To determine the possible blood types of their children, we can use a Punnett square:

| Mother (B+) | B | B |

|---|---|---|

| Father (0+) | O | ORh- |

| | O | ORh- |

The Punnett square shows that the possible blood types for their children are B+, B- (Rh-negative), 0+, and 0- (Rh-negative).

Therefore, it is not possible for the son to have a D RH negative blood type since neither parent has Rh-negative blood.