1. a white whale/a whale trained by the Russian navy (any 1)
4. (i) captivity
5. They have razor-sharp vision/stealth/good memory. (any 2)
6. military purposes
7. They wanted to see if they could be used by the military/to see whether they could guard entrances, assist deepwater divers or kill strangers. (any 1)
8. (i) meanwhile
9. Seals have a far better memory for remembering oral commands.