Final answer:
The four elements that compose 96% of living matter are oxygen, carbon, hydrogen, and nitrogen, which are crucial in forming biological molecules essential to life functions.
Step-by-step explanation:
Most Abundant Elements in Living Organisms
The four elements that make up approximately 96% of living matter are oxygen (O), carbon (C), hydrogen (H), and nitrogen (N). These elements are the building blocks for the major biological molecules such as nucleic acids, proteins, carbohydrates, and lipids which are essential for the structure and functioning of living organisms. While these elements are abundant in living organisms, in the non-living world they are found in different proportions. Understanding the unique structures of the atoms that comprise these molecules is critical for biologists who study how they contribute to the formation and function of cells, tissues, organ systems, and entire organisms.
Each of these elements plays a specific role in biological molecules. Carbon forms four chemical bonds allowing it to act as a central framework for organic molecules. Nitrogen forms three chemical bonds and is vital for building amino acids, the building blocks of proteins. Oxygen forms two bonds and is often involved in forming stable molecules important for cellular respiration and energy production, while hydrogen, forming one bond, is essential in forming water and organic compounds.