Oceanic plates are made up of a material called 'sima' that is mostly silicon and what other element?

Coral reefs support more species per unit area than any other marine environment on earth. what is one way coral reefs are important to the health of the biosphere

Me with these questions image attached

We can be sure that a mole of table sugar and a mole of vitamin c are equal in their 1) mass in daltons. 2) mass in grams. 3) number of molecules. 4) number of atoms. 5) volume.