Which of the following are pure substances? table salt, NaCl
water, H20
Oxygen, 02
elements
compounds
all of the above

1) describe the physical layout of the ocean floor ? 2) explain how the dumbo octopus swims differently than other octopus species and why this would be an advantage in the aphonic zone . 3) why are the types of organisms that live at each underwater hot vent so dramatically different ?