I have not studied this but to my best knowledge the answer is D.
Answer:
The word is connected through travel because It connects different cultures and people with different ideas. Such as when an American person goes to India and is inspired to learn more about indian cultures and ways of life. This leads on to communication because that same American needs to communicate with people in India to learn more about their culture
Explanation:
Travel and communication is connected through culture and ideas. If there was no communication then an idea would not be able to spread. If there was no travel then culture would not be able to be spread.
C. The inner core is known to be made mostly of nickel and iron. However, since there is an outer core (which is the original one that's made out of nickel and iron), your answer might be D. But if you put it the 'core' in general, the right answer should be C.