There is really nothing to know. All you have to use is context clues and common sense. We know some synonyms for direct are manage and handle. Indirect means not direct, right? And we can't handle or manage earth's interior (core), right? Therefore, the study of earth's interior is an example of indirect observation because we cannot directly manage it.
3. belonging in a large family they believe made you more elite
This is due to sahara desert and cold water current flowing on it
Answer:
people formed cultures because they want to make their own belief their own community of their own people to share that same belief.
