Final answer:
To regenerate body parts, complex organisms use mitosis, a cell division process that is crucial for tissue growth and repair. Photosynthesis and cellular respiration are metabolic processes vital for energy production but are not responsible for regeneration.
Step-by-step explanation:
Complex organisms use mitosis to regenerate body parts. Mitosis is a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth. This process is crucial for growth and repair within multicellular organisms, allowing for the replacement of cells and the regeneration of tissues. This is distinct from cellular respiration, photosynthesis, and fermentation, which are metabolic processes involved in energy production and conversion within cells.
Processes like photosynthesis and cellular respiration are metabolic pathways. Photosynthesis is how photosynthetic organisms like plants and planktonic algae capture the sun's energy to create carbohydrates, with oxygen as a by-product. Cellular respiration uses oxygen to break down carbon compounds like carbohydrates, producing CO₂ and ATP, which is the energy currency of cells. While these processes are fundamental to an organism's metabolism and energy production, they do not directly involve the regeneration of body parts.