21. Which answer best describes the coast?
A. thick deposits of sediments carried off of the shelf
B. the surf area along coastlines
C. 75 mile shallow flat area just off coastlines
D. area of land that drops toward deep ocean basins

C

Explanation:

75 mile shallow flat area just off coastlines

in chemistry, a solution’s concentration is how much of a dissolvable substance, known as a solute, is mixed with another substance, called the solvent. the standard formula is c = m/v, where c is the concentration, m is the mass of the solute dissolved, and v is the total volume

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.