Answer:
Ecological pyramids are diagrams that are used to show how much energy, the number of organisms, or how much biomass may be found at each trophic level of all the food webs of a community. Note that the autotrophs are always placed at the base of the pyramid.
Explanation:
"To help foster peace and economic collaboration among European nations" is the one among the following choices given in the question that <span>best describes the purpose of the European Union. The correct option among all the options that are given in the question is the first option or option "A". </span>
Group IV of the Periodic Table of the Elements contains carbon (C), silicon (Si) and several heavy metals. Carbon, of course, is the building block of life as we know it. So is it possible that a planet exists in some other solar system where silicon substitutes for carbon? Several science fiction stories feature silicon-based life-forms--sentient crystals, gruesome golden grains of sand and even a creature whose spoor or scat was bricks of silica left behind. The novellas are good reading, but there are a few problems with the chemistry.
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CRYSTALLINE CREATURES? Silicon can grow into a number of lifelike structures, but its chemistry makes it unlikely that it could be the basis for alien life-forms.</span>
Indeed, carbon and silicon share many characteristics. Each has a so-called valence of four--meaning that individual atoms make four bonds with other elements in forming chemical compounds. Each element bonds to oxygen. Each forms long chains, called polymers, in which it alternates with oxygen. In the simplest case, carbon yields a polymer called poly-acetal, a plastic used in synthetic fibers and equipment. Silicon yields polymeric silicones, which we use to waterproof cloth or lubricate metal and plastic parts.
Answer:
TRUE
Explanation:The all-or-none law is a principle that states that the strength of a response of a nerve cell or muscle fiber is not dependent upon the strength of the stimulus. ... Essentially, there will either be a full response or there will be no response at all for an individual neuron or muscle fiber.
