What causes the ocean's surface water to be warmer than water in the mixed zone or deep zone? a. salty water is denser than freshwater. b. icebergs melt near the ocean floor. c. the sun's rays hit the surface directly. d. upwelling pushes warm water to the surface.

answer: c

explanation:

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products