For question 7, I think the first part was asking why the glucose levels were different. I said something to the effect of: "The small intestine is where glucose is absorbed into the blood. This means there would be a high level of blood glucose in the portal vein leading from the small intestine to the liver. However, in the liver, some glucose is converted into glycogen by insulin to be stored there, and so the blood glucose level would fall, and therefore there would be less blood glucose in the hepatic portal vein leading away from the liver." (I may have got the portal and the hepatic portal vein the wrong way round).
The second part was asking why it had changed after six hours, I didn't really get this, I wrote the same thing for this and the last question. The last question was something like 'explain why the glucose level was higher in the hepatic portal vein than in the portal vein.' I wrote something like: "As he has not eaten over the last six hours, very little or no glucose is being absorbed into the blood in the small intestine, so the blood glucose level has fallen. Glucagon has been secreted by the pancreas to increase it. This converts glycogen in the liver back into glucose, and therefore the blood glucose level in the hepatic portal vein is higher because there is more glucose being released into the blood from the liver."