Nuclear power plant because that is a fission reaction and fusion would melt the power plant
The Curies discovered radium
Answer:

Explanation:
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In this case, since the molarity of a solution is computed by dividing the moles of solute by the volume of solution in liters, we first need to compute the moles of solute knowing that the molar mass of calcium hydroxide is 74.1 g/mol as follows:

Next, since the 100-mL solution is also expressed in liters by 0.100 L, we directly compute the molarity as shown below:

Which is expressed in molar units that are mol/L.
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Out of the three you gave ecosystem is what I would call the most broad. An ecosystem includes living AND non-living things in an area
Community is all the LIVING things in an area (plants are included and I think bacteria is too, but I'm not sure)
Population is pretty narrow it just looks at specific species in one area. Population of mosquitoes doesn't include butterflies, if only looks at mosquitoes
Hope this helped!