Respiratory organs in animals, irrespective of their habitat, have structures that increase the surface area for contact with the oxygen-rich atmosphere. These surfaces are often delicate, protected within the body, and connected to air passages for efficient oxygen exchange.

Fish take in water through their mouths, and it passes over their gills where dissolved oxygen is absorbed by the blood, facilitating respiration in an aquatic environment.

Terrestrial animals breathe oxygen from the atmosphere, while aquatic animals extract dissolved oxygen from water, leading to a faster breathing rate in aquatic organisms.

Plants exchange gases through stomata, and the large inter-cellular spaces ensure that all cells are in contact with air. Stomata facilitate the exchange of carbon dioxide and oxygen by diffusion, depending on environmental conditions and the plant’s requirements.

ATP, when broken down, provides a fixed amount of energy that drives endothermic reactions occurring in the cell, supporting various cellular processes.