In an amoeba, digestion occurs through a process called phagocytosis, where the cell engulfs food particles and forms a food vacuole that contains enzymes to break down the food inside. In contrast, a mouse has a more complex digestive system with specialized organs like the stomach and intestines, where food is broken down mechanically and chemically before nutrients are absorbed into the bloodstream. While the amoeba relies on its flexible cell membrane to take in food, the mouse uses its mouth and digestive tract to process food in a systematic way.
To explain this, I learned that amoebas, being unicellular, have to digest food directly where they take in and break it down all within one cell. Mice, as multicellular organisms, have dedicated organs for digestion which allows for more efficient processing and absorption of nutrients. If I were writing this for a 7th grader, I would say: "Amoebas eat food by wrapping themselves around it and breaking it down all inside their one cell. But mice have mouths, stomachs, and intestines to chew and digest food in a more organized way, which helps them get energy from what they eat better."