On a distant planet, there are four forms of life: zadohs, pugwigs, kahoots, and zingzangs. All zadohs are pugwigs. Some pugwigs are kahoots. All kahoots are zingzangs.

Which of these statements must then be true.

1. Some zadohs are zingzangs.
2. Some kahoots are zadohs.
3. All kahoots are pugwigs.
4. Some zingzangs are pugwigs.
5. All zingzangs are zadohs.
6. Some zadohs are kahoots.