Sucrose is

Which of the following statements is not true for sucrose?

$\alpha-D-(+)$-glucose and $\beta-D-(+)$-glucose are

Match the structures in Row $I$ with their names in Row $II$.
Row $I$:
$(P)$ $\alpha-D-(+)-$Glucopyranose
$(Q)$ $\beta-D-(+)-$Glucopyranose
$(R)$ $\alpha-D-(-)-$Fructofuranose
$(S)$ $\beta-D-(-)-$Fructofuranose
Row $II$:
$(i)$ $\alpha-D-(-)-$Fructofuranose
$(ii)$ $\beta-D-(-)-$Fructofuranose
$(iii)$ $\alpha-D-(+)-$Glucopyranose
$(iv)$ $\beta-D-(+)-$Glucopyranose
Correct match is:

Which of the following reduces Tollens' reagent?

Sugar is the main source of energy as it produces energy on metabolic decomposition. But these days low calorie drinks are more popular,why?