Which of the following is the best definition of convection? a) movement of heat through space b) melting of metal over a fire c) movement of hot materials due to density differences

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Which rate indicates the number of children that would be born per woman if she were to live to the end of her child bearing years

The picture represents the process that produces most of the energy used by living organisms on earth. which process is represented in the picture? a) the magnetic attraction between two hydrogen nuclei. b) the fusion of hydrogen nuclei to produce a helium nucleus in the core of the sun. c) the fission of hydrogen nuclei to produce a helium nucleus in the core of the sun. d) the chemical reaction between hydrogen nuclei to produce a helium nucleus in earth's atmosphere.