The answer is - c. serving in the military.
Just to be clear, serving in the military is not forbidden for Israeli Arabs, but it is the only thing that is not ''required'' of them to do. Israelies have to go to military service, while Israeli Arabs are not ''required'' to do that. Even though most of them don't do it, still there's the occasional exception where some of them want to go to military service and they do attend it.
Primary sources can be described as those sources that are closest to the origin of the information. They contain raw information and thus, must be interpreted by researchers. Secondary sources are closely related to primary sources and often interpret them.
The energy stored in rocks as a result of plate movement can be released in an earthquake.
The Rocky Mountains are described as younger because the Rocky's are really two mountain chains. The older mountain chain started billions of years ago, and the younger mountain chain pushed the older mountain chain up more, only 60 millions years ago.
