Which of the following is a characteristic of photosynthesis?

Photosynthesis is a vital process primarily occurring in plants, algae, and some bacteria, where they convert light energy, usually from the sun, into chemical energy in the form of glucose. One of the key characteristics of photosynthesis is that it produces oxygen as a byproduct. During this process, carbon dioxide and water are transformed into glucose and oxygen, facilitated by sunlight and chlorophyll, the green pigment in plants.

This oxygen, released into the atmosphere, is essential for life, as it is utilized by most organisms during cellular respiration. This characteristic emphasizes the significance of photosynthesis not just as a means for plants to generate energy, but also for contributing to the Earth's atmosphere and supporting a diverse range of life forms.

The other options do not correctly describe photosynthesis: it does not occur in animals, it does not release carbon dioxide (instead, it consumes it), and it does not require dark conditions since it requires light to initiate the process.