which characteristics would one expect to find when
studying the cooled lava?

idk what the options are but

these is a strong electrostatic attraction between the ions hence a lot of energy is needed to overcome this attraction

this is why the boiling points are so high

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.