Which type of respiration occurs constantly in both plants and animals?

Aerobic respiration is the correct answer because it is a metabolic process that occurs continuously in both plants and animals. This type of respiration requires oxygen to convert glucose into energy, with carbon dioxide and water being produced as by-products. In both groups of organisms, aerobic respiration forms the backbone of energy production, enabling them to carry out vital functions necessary for survival.

In contrast, anaerobic respiration occurs in the absence of oxygen and typically transpires in specific conditions or during intense activity. While fermentation is a type of anaerobic respiration found in some organisms, such as yeast, it is not the predominant method of respiration for either plants or animals under normal conditions. Photosynthesis, while crucial for plants and the production of glucose, is a separate process that takes place only in the presence of light and is not an ongoing mode of respiration like aerobic respiration.