4. D. livestock
5. C. To obtain creatine that improves protein synthesis.
6. I agree that we have to reduce meat consumption, if we cannot avoid it as a whole.
Looking at meat production, livestock, the emissions and its damaging impact on our environment, I think this is the time for us, humans, to realize and aware that we should protect the planet before it's too late.
(TribunnewsBogor.com/Tia)