Question

president reagans plans for the strategic defense initiative
pressured the ussr into building a similar system.
decreased the number of us nuclear weapons.
ended the cold war.
provided an opportunity for peace talks.

Explanation:

The Strategic Defense Initiative (SDI, or "Star Wars") was a proposed missile defense system by President Reagan. The USSR, strained by economic issues, attempted to develop a comparable system, which further drained their already limited resources, increasing pressure on the Soviet regime. The other options are incorrect: SDI did not directly decrease US nuclear weapons, it was not the sole cause of ending the Cold War, and it initially escalated tensions rather than immediately creating peace talk opportunities.

Answer:

pressured the USSR into building a similar system.