Karl Landsteiner and Alexander Wiener discovered the Rh factor in 1940. This red blood cell surface antigen dictates an individual's Rh-positive or Rh-negative blood status, a crucial element in blood transfusions and pregnancy.
| LIST I | LIST II | ||
|---|---|---|---|
| A | Chop wound | I | Axe |
| B | Punctured wound | II | Needle |
| C | Bruises | III | Whip |
| D | Incised wound | IV | Knife |