What is the linkage connecting monosaccharides in a polysaccharide called?

Glucose and Galactose have identical configurations at all positions except position:

Maltose on hydrolysis gives two monosaccharide units. The incorrect statement about the monosaccharides formed is

How many optical isomers does glucose have?

When sugar $X$ is boiled with dilute $H_{2}SO_{4}$ in an alcoholic solution,two isomers $A$ and $B$ are formed. $A$ on oxidation with $HNO_{3}$ yields saccharic acid,whereas $B$ is laevorotatory. The compound $X$ is ....... .

What is the structure of $L$-glucose?