What is the contour interval in the map?

Contour interval in  surveying is the vertical distance.

Explanation:

Normally there are different contour intervals for different maps.The size of the area considers the contour intervals. In each and every map on the right hand bottom side the contour interval is specified.Therefore a contour interval is difference in two elevation between the contour lines in a topographical map

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation:

answer; /// i believe that the correct answer is ( monophasic ); ethinyl estradiol- ethynodiol diacetate is a monophasic oral contraceptive agent; ///