Soil scientists use the capital letters O, A, B, C, and E to identify the master soil horizons<span>, and lowercase letters for distinctions of these horizons. Most soils have three major horizons: the surface horizon (A), the subsoil (B), and the substratum (C). Some soils have an organic horizon (O) on the surface, but such a horizon can also be buried. The master horizon, E, is used for subsurface horizons that have a significant loss of minerals (eluviation). Hard bedrock, which is not soil, uses the letter R.</span>
The chemicals, neurotransmitters are released to carry a nerve impulse which is an electric signal transmitted by the nervous system. This impulse transmitted from one neuron to another. Examples of neurotransmitters are serotonin in which scientists thinks that a low level of this is one of the causes of depression.
I think the answer would be needs. Hope this helps.
Troponin-tropomyosin molecules prevents a muscle contraction from occurring when the muscle is at rest.
<h3>What is
muscle contraction?</h3>
The activation of tension-producing regions within muscle cells results in muscular contraction. Because muscle tension can be created without changes in muscle length, such as when holding something heavy in the same position, muscle contraction does not always imply muscle shortening in physiology. Muscle relaxation, or the return of the muscular fibers to their low tension-generating state, occurs after a muscle contraction has finished.
Both length and tension can be used to characterize muscle contractions. If the muscle tension varies but the muscle length doesn't, the muscle contraction is said to be isometric. A muscle contraction is isotonic, however, if the tension in the muscle remains constant during the contraction.
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Monosaccharides are simple sugar unit molecules, whereas polysaccharides are enormous, linking thousands of sugar units. Monosaccharides provide cells with short-term energy. Polysaccharides provide long-term energy storage and rigid structure to cell walls and exoskeletons of animals.
