Here's why:
* Photosynthesis: Plants use sunlight, water, and carbon dioxide to produce their own food (glucose) and release oxygen as a byproduct. This is the defining characteristic of plants.
* Respiration: All living organisms, including plants, need to break down food (glucose) to release energy for their life processes. This process is called respiration and requires oxygen.
While other kingdoms have organisms that can carry out either photosynthesis or respiration, only plants perform both processes regularly as their primary mode of energy production and utilization.
