Beginning of Essay
The sea is the most obvious feature of the earth's surface. Approximately seventy percent of this surface is covered by water, in one way or another. Beneath this water are the familiar sands of the beaches, bottoms of bays, and the inshore ocean. Farther offsho ....

Middle of Essay
.... its density, and the differences in density are the major factor in understanding the formation of currents and the positions of water masses in the sea. In addition, temperature and salinity play major roles in influencing the distribution of plants and animals. The sediments of the sea floor may be divided into lithogenous, hydrogenous, biogenous, and cosmogenous sediments. Lithogenous sediments are the major sediments on the ocean floor. They are derived from the chemical and mechanical weathering of rocks. Biogenous sediments are composed primarily of the protective outter covering of small marine animals and plants. If these remains com ....