1.Pointing to the house on whose roofs grew lots of bush,the

1.Pointing to the house on whose roofs grew lots of bush,the old man told me that was___i would stay.
where
2.Because of ___high demandfor Type AB blood,___supplies of it are usually limited.
a,the.
请具体解释下.
1.为什么不用what或which?
2.可是high不可数，为什么用a;supplies显然是可数复数，虽然是特指，但为什么要加the?