A mass of 68.45 g of nickel (II) sulfate hydrate, NiSO4∙ nH2O, loses 28.40 g upon dehydration. What is the hydration number of this compound? (Find n.)

May someone me with these science questions

Which answer tells the reason the earth’s climate is getting warmer? too many animals are becoming extinct. large glaciers are melting in antarctica. the earth is moving closer to the sun. driving cars gives off gases that trap heat in the atmosphere.

Why is it possible for different microorganisms to extract energy not only from carbohydrates and other biological molecules but from a large variety of substances?