Before food enters the mouth, digestion begins when humans start to __ about food.

• A. Plan
• B. Think
• C. Smell
• D. Taste

Answer: (B)

When you think about food, your brain sends signals to start preparing the digestive system before anything is in the mouth. This anticipatory phase, driven by the parasympathetic nervous system, makes the body ready to digest. Thinking about food prompts the salivary glands to begin producing saliva, which moistens and starts enzymatic activity (like starch digestion) right away. It also primes the stomach for upcoming secretions, so digestion gets a head start as soon as food arrives.

That’s why thinking about food is the best fit for the prompt: it describes the cognitive cue that triggers this early, preparatory response. Planning isn’t a direct physiological trigger, smelling is a sensory cue that could prompt digestion but the statement specifically emphasizes thinking, and tasting happens after the food is in the mouth.