fragile – adj. easily broken or damaged

ballistic missile – n. a weapon shot through the sky over a big distance and then falls to the ground and explode

uranium – n. a radioactive element used to make nuclear weapons

cusp – n. the edge of something

centrifuge – n. a machine that spins substances inside a container around very fast, causing the heavier substances to move to the bottom or sides of the container.

veto – n. a decision by a person in authority to not allow or approve something