What is clear here is that sedation was provided by a physician or other qualified health care professional. Read at the CPT Coding Changes For Moderate Sedation in 2017. It states there will be several codes for moderate sedation. Your statement of the case is not complete, as age is important. The codes for moderate sedation is 99151 to 99157.
The answer would be a. Energy stored in chemical bonds :)
7. Succession, 6. Extinction, 5. Niche, 3. Ecosystem, 2. Population, 1. Habitat, 4. Environment, 8. Community