SAT Subject Biology Practice Question 154: Answer and Explanation
4. People with an A-positive blood type may safely donate blood to those with which blood type?
A. A negative
B. B positive
C. O negative
D. AB positive
E. AB negative
Correct Answer: D
Blood recipients that lack the A antibody cannot receive blood from donors with the A antibody (blood types A and AB). Positive and negative blood types refer to Rh system (specifically, the D antibody). Recipients that lack this antibody (negative) cannot receive blood from positive donors. Therefore, the only safe recipients of A-positive blood are A positive and AB positive.