Which from following compounds contains oxygen as a heteroatom?

What type of glycosidic linkages are developed when excess glucose is to be stored for future use in animals?

Calculate the relative lowering of vapour pressure if vapour pressure of pure solvent and vapour pressure of solution at $25^{\circ} \mathrm{C}$ are 32 and 30 mm Hg respectively.

Which from following ligands is neutral?