Which one of the following compounds is found abundantly in nature?

Which of the following sugars is the sweetest?

Assertion : Hydrolysis of sucrose is known as inversion of cane sugar.
Reason : Sucrose is a disaccharide.

Given $D$-Glucose. The compound$(s)$,which on reaction with $HNO_3$ will give the product having degree of rotation,$[\alpha]_{D}=-52.7^{\circ}$ is (are)

The carbohydrate which does not react with ammoniacal $AgNO_3$ solution is

Which of the following pentoses exhibit optical activity?

$I$. $CHO-CH(OH)-CH(OH)-CH(OH)-CH_2OH$	$II$. $CHO-CH(OH)-CH(OH)-CH(OH)-CH_2OH$
$III$. $CHO-CH(OH)-CH(OH)-CH(OH)-CH_2OH$

(Note: The structures provided are $I$: Ribose,$II$: Arabinose,$III$: Xylose. All these are aldopentoses with chiral centers.)