1) Potection of animals is important because some of them are endangered because of poachers, who kills animals for meat, fur/leather or just for trophy.
2) Environmental pollusion, dirty rivers/lakes and polluted air can injure animal's health.
3) Amur tiger, African elephant, elephant turtle, chimpanzee, Galapagos Sea Lion, western gorilla, Grevy's zebra, orangutan, rhinoceros, big panda, Magellanic penguin, polar bear, sifak, Grizzly bear.
4) I think that first of all, animals should be bred in captivities untill there will be enormous amount of them, only then they can live in the wild. But there is still would be risk that animals will be killed by hunters and poachers again.
5) Animals are locked in small cages, surrounded by humans and there's no peace and quiet for them. When they need more movements, they got to lying on the floor all the time. Of course it's prison for them.
6) All the times, the most popular pets was cat and dog. Also, many people keeping a hamsters, parrots and fishes.
7) Animal shelters always trying to save them and find a owners. Also, there is a World Animal Protection organisation, that helps animals who are victims of the natural disasters or wars, or just homeless and ownerless animals that left in the streets.