In 2Cr2O7 there’s 2 items; Cr and O
3. Millions of years ago, the Earth was not divided into 7 continents. It was only a very large land mass, the scientists named that one land mass “Pangaea”
4. If the tectonic plates are disturbed, they can cause mass earthquakes and tsunamis.
5. The ring of fire is a massive collection of volcanoes under the pacific ocean. They all form the shape of a ring, hence the name.
SORRY, I COULDNT ANSWER THE FIRST TWO QUESTIONS.
