Steel has the highest specific weight among the materials listed, with an approximate value of 7.85 g/cm³. Concrete follows at 2.4 g/cm³, FRP composites range from 1.0 to 2.0 g/cm³, and wood averages from 0.5 to 0.9 g/cm³. Therefore, the answer is Steel.
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Steel has the highest specific weight among FRP composites, concrete, and wood, with a specific weight of approximately 7.85 g/cm³. Concrete follows at 2.4 g/cm³, while FRP composites range from 1.0 to 2.0 g/cm³, and wood ranges from 0.5 to 0.9 g/cm³. Thus, steel is the densest material in this comparison. ;