How do scientists classify living things based on characteristics?

All living organisms are classified into groups based on very basic, shared characteristics. Organisms within each group are then further divided into smaller groups. The classification of living things includes 7 levels: kingdom, phylum, classes, order, families, genus, and species

Explanation:

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.