Final answer:
Gastrointestinal activity in animals affects intestinal cell growth, gastric acid production, esophageal function, and gallbladder performance, with the autonomic nervous system playing a crucial regulatory role.
Step-by-step explanation:
The aspects influenced by gastrointestinal activity in animals include intestinal cell growth, gastric acid production, esophageal function, and gallbladder performance. The gastrointestinal mucosa is crucial for nutrient absorption and protecting against pathogens, while gastrointestinal secretory activity regulates the release of enzymes and acid for digestion. The autonomic nervous system plays a significant role in controlling these processes: sympathetic nerves can decrease gastrointestinal secretion and motility, whereas parasympathetic nerves increase them to facilitate digestion.