Select the correct statement about the human digestive system.

All the four layers of the wall of alimentary canal show modifications in different parts of the alimentary canal.

The endocrine portion of the pancreas secretes enzymes while exocrine portion secretes hormones.

The upper surface of the tongue has small projections called papillae, all of which bear taste buds.

Four pairs of salivary glands situated just outside the buccal cavity secrete saliva into the oral cavity.