Why is the holocaust important as why world war one is important?

This was an order issued during the civil war by president lincoln ending slavery in the confederate states

What is the evidence that depression can be linked to genetic as well as environmental factors? a. all individuals in similar stressful environments do not experience depression. b. all individuals with the gene variation tied to depression do not experience depression. c. individuals with a combination of environmental stress and gene variation are more likely to experience depression d. all of the above select the best answer from the choices provided оа 0 0 0

The answer because i don’t know it someone