Answer:
C
Explanation:
Density is equal to the ratio of mass and volume. Mass is the amount of matter or substance of a body and volume is the space occupied by it. Density is the unit amount of matter or substance contained in unit volume.
Down the great rivers that flow into the Baltic Sea. Then the sailors would portage (carry and drag) their ships between rivers, heading for southern flowing rivers, such as the Dneiper and Don,