The ocean has a tremendous amount of salts dissolved in its water and is very warm around the tropics. Yet these regions of earth house millions of aquatic species. Explain
how the warm salty waters around the equator can still produce enough dissolved
oxygen to support life.

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.