Aside from the fact that I had a nightmare with this paper could someone please answer the question in the IHT question that asked why it's more beneficial to leave your estate to grandchildren rather than children?

I'm at a complete loss, wrote nothing! I know that was only 2 points so no big deal(least of my worries) but its bugging me!

Did everyone else have lots of Cs in the Multiple Choice Question?

The basic reason is to avoid the same asset being taxed twice before getting to the grandchildren. If you leave them to your children, it will be taxed. When your children transfers same asset to your grandchildren, it will be taxed again!