Some animals eat their feces to digest the cellulose contents again; such animals are known as:

$A$ patient suffering from cholera is given a saline drip because:

$A$ healthy person eats the following diet: $5 \, gm$ raw sugar,$4 \, gm$ albumin,$10 \, gm$ pure buffalo ghee adulterated with $2 \, gm$ vegetable ghee (hydrogenated vegetable oil),and $5 \, gm$ lignin. How many calories is he likely to get?

Assertion : In the condition of obstructive jaundice,large amounts of unabsorbed fats are eliminated out of the body.
Reason : Entry of bile into the small intestine is prevented during obstructive jaundice.

$A-$ About $30\%$ of starch is hydrolyzed by salivary amylase (optimum $pH\, 6.8$) in the buccal cavity.
$R-$ The saliva secreted into the oral cavity contains electrolytes $(Na^+, K^+, Cl^-, HCO_3^-)$ and enzymes,salivary amylase and lysozyme.

Which one of the following vitamins can be synthesized by bacteria inside the gut?