What are the similarities in the structure of the bodies of living organisms?

All living organisms, regardless of the level of organization, are composed of the same chemicals – proteins, fats and carbohydrates. These chemical compounds are composed primarily of oxygen, hydrogen, carbon and nitrogen atoms, which are found in all living organisms.
All organisms need lipids to build cell membranes. From the protozoa to humans, all cell membranes are composed of lipids.
Proteins are used as building materials. All the enzymes that organisms need for life are also of protein origin.
Carbohydrates are used for energy by any organism. Without them, it would be impossible to exist.