Well for the very last sentence it would be if any of the organs shut down it could seriously hurt someone or possibly even kill them if their brain,heart or some other important organ shuts down it could kill them.
There are other minor organs where if it shuts down it wouldn't really hurt the person too much. Sorry I couldn't help you with the other ones though.
Insulin is released into the blood when oxygen levels are low and blood glucose levels are high
I think you are right. B is the right answer.
Not always, the toxins may have been absorbed by the body and released in urine
