With reference to hypersonic missiles like Iran’s Fattah-1, consider the following statements: 1. All ballistic missiles are hypersonic by definition. 2. Hypersonic glide vehicles differ from ballistic missiles in flight path and manoeuvrability. 3. The key threat posed by hypersonic weapons is their ability to deliver nuclear warheads. 4. Hypersonic missiles fly exclusively outside the Earth’s atmosphere.