The GCF of the first two terms: 5h²
The GCF of the last two terms: 4
5h³ and 20h²
Both of these terms are divisible by 5. (constant)
Both of these terms also have at least 2 h's. (variable)
4h and 16
Both of these terms are divisible by 4.
Only one term has a variable, so that has to be left out.