An answer might be - <span>Any of a group of complex organic macromolecules that contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur and are composed of one or more chains of amino acids. Proteins are fundamental components of all living cells and include many substances, such as enzymes, hormones, and antibodies, that are necessary for the proper functioning of an organism. They are essential in the diet of animals for the growth and repair of tissue and can be obtained from foods such as meat, fish, eggs, milk, and legumes.
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The majority of Earth's atmosphere contain 78% is nitrogen, The Nitrogen cycle is the geochemical cycle in which nitrogen is converted into multiple chemical forms. Nitrogen cycle occurs in terrestrial and marine ecosystem. Nitrogen can be converted through both biological and physical process. The processes that are involved in nitrogen cycle are fixation, ammonification, nitrification, and denitrification.
There is limited amount of nitrogen that is useful but <u>increase of fossil fuel combustion, use of artificial nitrogen fertilizer</u> have dramatically increased the amount of nitrogen in nitrogen cycle.
The structure and shape of each type of human cell depends on what function it will perform in the body. For example, red blood cells (RBCs) are very small, flat discs, which allows them to easily fit through narrow capillaries and around sharp corners in the circulatory system to deliver oxygen throughout the body.
The elongated shape of muscle cells allows the contraction proteins to line up in an overlapping pattern that makes muscle flexing possible.
And human sperm cells’ structures allow them to “swim” long distances to reach an egg for fertilization
