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.
The sand dollar's mouth has a jaw with five teethlike sections to grind up tiny plants and animals. Sometimes a sand dollar chews its food for fifteen minutes before swallowing. It can take two days for the food to digest.Scientists can age a sand dollar by counting the growth rings on the plates of the exoskeleton.Sand dollars usually live six to 10 years. California sheepheads, starry flounders and large pink sea stars prey on sand dollars. When threatened by pink sea stars, sand dollars bury themselves under the sand.ometimes a sand dollar chews its food for fifteen minutes before swallowing. It can take two days for the food to digest. Scientists can age a sand dollar by counting the growth rings on the plates of the exoskeleton. Sand dollars usually live six to 10 years.