Correct Answer: Acid contents going back up into the esophagus

Herbivores mainly consume cellulose which is a complex saccharide. It takes longer time to get digested. Meat is comparatively easily digested. Thus, carnivores have smaller intestine.

Small intestine is specially designed with finger-like projections called villi for absorption of food. Villi increase the surface area and thus, increase the efficiency of absorption.

Bile required for the digestion of fats is stored in the gall bladder.

Digestive enzymes in paramecium are produced in the cytoplasm. They move inside the food vacuole and digest the food contents.

Bile is probably absent in his digestive tract. Fats are passing out undigested as is evident from the greasy stool. Bilirubin is not getting excreted. Thus, the stool is white.

a, c and d are the processes carried out by the desert plants. They take up CO₂ at night. Intermediates are prepared at night. Stems carry out photosynthesis.

Plants absorb nitrogen from the soil in the form of nitrates.

It is untrue. Chyme is expelled to the duodenum from the stomach.

Inability to digest milk sugar is known as lactose intolerance, which is caused by lactase deficiency. This enzyme helps in the digestion of lactose.

Pancreas synthesises enzymes for digestion of proteins, carbohydrates and fats. It produces pancreatic amylase for carbohydrate digestion, pancreatic lipase for fat digestion and trypsin for protein digestion.

Leech is an ectoparasite. It lives on the host and sucks blood.

Streptococcus mutans is a common microbe that is associated with dental plaque formation.

Intestines do not secrete trypsin. It is produced and secreted by pancreas.

Enzyme pepsin digests proteins. Pepsin is secreted by the stomach and requires acidic conditions to manifest its action.