Digestion of food is a complex process that includes many feedback loops. in the simplified diagram of digestion that is shown in figure 28.3, food enters the stomach, and a hormone called gastrin carries a message to a target. what happens first when the message reaches its target?

Digestion is a complex process, in which complex food substances are broken down into simpler forms.

Gastrin is a compound produced in the stomach during the digestion of food substances.

In the given feedback loop, the food when entering the digestion cycle, the gastrin will be secreted, causing the increase in the release of gastric juice. The acidic environment will activate the enzyme pepsin, which lowers the pH inhibiting the release of gastrin.

The gastrin inhibition will lead to an increase in the pH, and thus, the loop will be followed the same way for digesting the food.

Thus, the food when reaches the stomach it will cause the release of gastrin.

To know more about gastrin, refer to the following link:

link

b. heterotroph

explanation: