Author believes that animals are people's helpers, and we should use them to our comfort and survival. He thinks that it is morale acceptable, because we really need them for safety, comfort and progress of humanity, that it is worth to sacrifice one animal life for millions human's lives.
Paragraph:
1 E (conclusion)
2 C (present)
3 B (present your)
4 D (explain)
5 A (intoduce)