Why did the Nazis never use Chemical or Biological weapons in WWII in combat? Ok

They feared that there enemies would retaliate with their own chemical/biological weapons against the Nazis.

Explanation:

well since twins have about the same dna they dont have one think in common which is the figer print. nobodys fingerprint is the same. if your using twin you would most likely get around the same results for both of them because of the genetics.. i hope this