Got Questions?

I get confused sometimes about the difference between cities and countries. Can someone explain with examples? For instance, is London a city or a country?

I'm doing a project on important inventions and need to know who invented the telephone and when. Was it Alexander Graham Bell or was there someone else involved too?

I noticed that different countries celebrate different festivals. Why is that? How did these festivals start and why are they important to people?

I'm confused between the Pacific Ocean and the Atlantic Ocean. Which one is bigger and by how much? Also, how many oceans are there in total?