Final answer:
Sugar, or more specifically glucose, is the missing component from the process of cellular respiration, which is necessary to produce ATP, carbon dioxide, water, and energy.
Step-by-step explanation:
The component missing from the process of cellular respiration is sugar, specifically glucose. The complete equation for cellular respiration is glucose (C6H12O6) + oxygen (O2) → carbon dioxide (CO2) + water (H2O) + energy. During this process, cells break down glucose in the presence of oxygen to release carbon dioxide, water, and energy. Glucose is a crucial part of the equation as it is the fuel that cells use to generate ATP (adenosine triphosphate), which powers most cellular activities.
Photosynthesis is the process in which cells use energy from sunlight to convert carbon dioxide and water into glucose and oxygen. Thus, the glucose produced during photosynthesis becomes the energy source for other living organisms through cellular respiration.