3 ms·

tldr someone ? :D

• maxerickson 10y ago
  It's not that kind of article.
• eric_h 10y ago
  It's complicated.
• pwinnski 10y ago
  "More than a century after their discovery, we still don’t really know what blood types are for. Do they really matter? Carl Zimmer investigates."
• ClassyJacket 10y ago
  "Don't know."