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This is a list of some well-known periodic functions. The constant function f (x) = c, where c is independent of x, is periodic with any period, but lacks a fundamental period. A definition is given for some of the following functions, though each function may have many equivalent definitions.
Ubiquitous, essential for all forms of life; all proteins and nucleic acids contain substantial amounts of nitrogen. [11] Toxic in some forms. [11] osmium: 76: 1a: None known. [11] Osmium is very rare, substantially more so than any element essential to life. [3] The oxide is toxic to humans. [11] oxygen: 8: 5
Periodic motion is motion in which the position(s) of the system are expressible as periodic functions, all with the same period. For a function on the real numbers or on the integers , that means that the entire graph can be formed from copies of one particular portion, repeated at regular intervals.
Death is the termination of all vital functions or life processes in an organism or cell. [31] [32] One of the challenges in defining death is in distinguishing it from life. Death would seem to refer to either the moment life ends, or when the state that follows life begins. [32]
All 11 are necessary for life. The remaining elements are trace elements, of which more than a dozen are thought on the basis of good evidence to be necessary for life. [1] All of the mass of the trace elements put together (less than 10 grams for a human body) do not add up to the body mass of magnesium, the least common of the 11 non-trace ...
Life functions through the specialized chemistry of carbon and water, and builds largely upon four key families of chemicals: lipids for cell membranes, carbohydrates such as sugars, amino acids for protein metabolism, and nucleic acid DNA and RNA for the mechanisms of heredity. Any successful theory of abiogenesis must explain the origins and ...
Like the periodic table, the list below organizes the elements by the number of protons in their atoms; it can also be organized by other properties, such as atomic weight, density, and electronegativity. For more detailed information about the origins of element names, see List of chemical element name etymologies.
The most known chemical elements whose covalent combinations make up most biological molecules on Earth. [2] All of these elements are nonmetals.. In animals in general, the four elements—C, H, N, and O—compose about 96% of the weight, and major minerals (macrominerals) and minor minerals (also called trace elements) compose the remainder.