Step 1: Understanding the Concept
Humans have three pairs of salivary glands: parotid, submandibular and sublingual.
Step 2: Check each statement
Parotid glands lie in front of the ears, so A is true. Serous cells make a watery juice containing salivary amylase, so C is true. Mucus lubricates food and helps form the bolus, so D is true.
Step 3: Find the wrong one
Sublingual glands lie beneath the tongue. The glands near the lower jaw are the submandibular glands, so statement B is wrong.
Final Answer:
The incorrect statement is that sublingual glands are below the lower jaw.
\[ \boxed{\text{(B) }\text{Sublingual glands are present below the lower jaw}} \]