When we write the formula for an ionic compound, we are merely indicate the "molecules" in the compound with that formula. explain?

Who is better, messi or cristiano, i need this for a chemistry class. asap

Iknow the answer is a but i don't know why

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 ?