The half-life of uranium-235 is 700 million years, if there is 1000g of urnanium-235 in the original sample, what happens after 2100 million years have passed?

Aplanet similar to earth has four moons roughly the same distance away. the moon that will most affect tides on the planet is the one that has the greatest a) mass. b) volume. c) density. d) amount of water.