In subduction, what determines which plate will be on top and which will be on bottom?

What are simmilarities and differences between anaerobic respiration in animal and yeast cells? would prefer to get simmilarities as i already got some differences. you!

When ash and dust begin to settle on the ground, they eventually become compacted by

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?