Lesson Objectives. 1  List the main features of the seafloor: mid-ocean ridges, deep sea trenches, and abyssal plains. 2  Describe what seafloor magnetism tells scientists about the seafloor. 3  Describe the process of seafloor spreading.
Assignment Help. The average diameter of sand dollars on a certain island is 4.50 centimeters with a standard deviation of 1.00 centimeters. If 9 sand dollars are chosen at random for a collection, find the probability that the average diameter of those sand dollars is more than 4.13 centimeters.he average diameter of sand dollars on a certain island is 4.50 centimeters with a standard deviation of 1.00 centimeters.
Sand dollars are the fused calcium-based shells of a type of sea urchin. These sea urchins are burrowers that feed on tiny organisms in ocean sediment. Their burrowing lifestyle means their spines must be very short, and their bodies are flattened and slightly elongated to enable them to move through sediment more easily. Keep Learning.