Exercise 6.1.1

What are the minimum and maximum numbers of elements in a heap of height $h$?

It is between $2^n$ and $2^{n+1} - 1$. For example, a heap with $2$ ($2^1$) or $3$ ($2^2 - 1$) will have height $1$. If there are four elements, however, the heap height will be $2$.