What would happen if two oceanic plates move away from each other at a divergent boundary

Why is excretion necessary to maintain homeostasis?

Which statement best describes the role of religion and culture in ancient medicine?

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?