Which explanation best describes the relationship between salinity, temperature, and nutrient concentrations across latitudes?

At higher latitudes, surface waters generally become colder and less salty, while mixing and upwelling bring nutrient-rich deep water toward the surface. This links declining temperature and salinity with greater nutrient availability, as choice D states. Warm, salty low-latitude surface waters are often nutrient-poor, so choice A reverses the typical relationship.

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