Which of the following pairs of scientists discovered the Rhesus factor in human blood?

Analyze the question: You're asked which pair of scientists discovered the Rhesus (Rh) factor in human blood.

Explain the concept: The Rhesus factor is an antigen (protein) on the surface of red blood cells. If you have it, you are Rh positive. If you don't, you are Rh negative. It matters in blood transfusion and in pregnancy (Rh incompatibility between mother and baby).

Key scientists:

• Karl Landsteiner discovered the ABO blood groups in 1901. In 1937, together with Alexander Wiener, he identified the Rh factor in 1940 using rhesus monkeys, which is how it got its name.
• Alexander Wiener is the usual co-discoverer credited alongside Landsteiner.
• Philip Levine also worked on the Rh factor. He and Rufus Stetson (1939) linked it to haemolytic disease of the newborn.
• Robert Hooke discovered cells (1665), and Charles Darwin proposed evolution by natural selection. Neither has anything to do with blood.

Eliminate the options:

• A. Hooke and Lavine: Hooke is wrong, so this is out.
• B. Darwin and Landsteiner: Darwin is wrong, so this is out.
• D. Hooke and Darwin: neither is connected to blood groups, so this is out.
• C. Landsteiner and Lavine: both worked on the Rh factor. "Lavine" is the JAMB spelling of Levine, and this is the only pair made up of blood scientists.

Note: Strictly speaking, the textbook pairing is Landsteiner and Wiener. But Wiener is not among the options, and Landsteiner and Levine are both genuinely tied to Rh research, so C is the only sensible choice.

Answer: C. Landsteiner and Lavine

Exam tip: Link names to discoveries:

• Hooke → cells
• Darwin → evolution
• Landsteiner → blood groups (ABO and Rh)

If you see Landsteiner in a blood question, look for the option that pairs him with another blood scientist, not a cell or evolution scientist.