The letter '$D$' in carbohydrates signifies

The reaction of glucose with acetic anhydride confirms the:

What is the total number of carbon atoms present in a sugar molecule of $RNA$ nucleotide?

Provide the missing details in the following reactions:
$C_{12}H_{22}O_{11}$ $\xrightarrow{A = (?)} C_6H_{12}O_6$ $\xrightarrow{B = (?)} 2C_2H_5OH + 2CO_2$

Which one of the following compounds will form an osazone derivative?

At which carbon atom do $\alpha-$ and $\beta-$ glucose differ in the configuration of the $-OH$ group?