Which of the following activities would represent a physiological study? observing the structure of the interior of the heart studying a model of the kidney examining the surface of a bone viewing muscle tissue through a microscope determining normal blood sugar levels for 20 -year-old students

A physiological study focuses on the functions and processes occurring within living organisms. Let's evaluate each activity: 1. **Observing the structure of the interior of the heart**: This is more related to **anatomy**, which deals with the structure of organs and tissues. 2. **Studying a model of the kidney**: While it can involve understanding kidney functions, if the focus is primarily on the model's structure, it's more anatomical. However, if the study emphasizes how the kidney functions, it could be considered physiological. 3. **Examining the surface of a bone**: This is primarily an **anatomical** study focusing on structure rather than function. 4. **Viewing muscle tissue through a microscope**: This involves **histology**, the study of tissues, which is more structural but can relate to physiological functions if examining how muscle fibers contract, for example. 5. **Determining normal blood sugar levels for 20-year-old students**: This directly involves understanding a **physiological process**—how the body regulates blood glucose levels. **Therefore, the activity that best represents a physiological study is:** **Determining normal blood sugar levels for 20-year-old students.**