Genocide is the murder of 100's or thousand's of people. The holocaust could be considered mass genocide of the Jews.
Hope that helps :)
Because they hid the people and made sure they were the only ones who got to keep tabs
Even though synonyms generally share the same meaning, they might not apply in the same context. So, if you want to use one specific word you should do that instead of trying to find a synonym that doesn't quite fit into the context you've established. An example is if you want to use the sentence "I was mad", meaning "I was angry", you could look for a synonym. One synonym is "absurd". However, this is a different type of mad, meaning crazy instead of meaning angry. "I was absurd" has an entirely different meaning than originally intended. This is why you should always double check the contextual meaning of the synonym you want to use.
Eliza's appearance as a prim and proper beautiful young lady coupled with her perfect English accent surprised the guests; and they began to speculate as to where she came from. As they listened to her talk, they found her weird but Prof. Higgins explained that it was the "new small talk."