Which of the following elements will most likely form an anion to achieve an octet?

Which characteristics can be used to differentiate star systems? check all that apply.

Can someone me with 3 and 4 plz. this is for masteries test.

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 ?