List of Words for Letter ‘R’
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radiation The
energy given off by a radioactive element.
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radioactive A
type of element that gives off energy in the form of rays or particles.
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rain shadow A
region on the side of a mountain where air becomes dry and descends.
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rarefaction An
area where particles in a medium are spread apart by a wave’s energy.
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reactant An
original substance at the beginning of a chemical reaction.
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recessive trait The
hidden form of an inherited trait which will only show in the phenotype if it is paired with another recessive gene.
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reflection How
a wave bounces off an object and changes its direction of travel.
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refraction The
change in direction of a wave because of a change in the medium it is traveling through.
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renewable resources Materials from the environment that people use. Resources are either renewable, meaning they can be replaced relatively quickly, or nonrenewable, meaning that there is a limited quantity available.
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reproduction The process that a living thing uses to produce more of its own kind. May be asexual or sexual.
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reservoir A
natural or artificial lake that stores supplies of fresh water.
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resistor A
material through which electricity has difficulty flowing.
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respiration The
process of releasing energy from food molecules such as glucose, which takes place in the mitochondria of a cell.
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revolution One
complete trip orbiting around an object, such as Earth orbiting the Sun.
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rock cycle The
process in which rocks continuously change from one kind into another over long periods of time.
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root A plant part that anchors a plant in the ground, stores food, and draws moisture and nutrients from the soil.
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rotation One
complete spin of an object such as Earth on its axis.