- The relation (house, complete mailing address) is a function, but the relation (complete mailing address, house) is not.

Explanation:
To determine if these two groups form a function, we need to consider the definition of a function in mathematics. A function relates each element in the domain to exactly one element in the codomain.
In this case, we have two groups: "house" and "complete mailing address." If "house" is the domain and "complete mailing address" is the codomain, then we need to check whether each element in the domain (house) is related to exactly one element in the codomain (complete mailing address).
If "house" represents different houses, and each house corresponds to a unique complete mailing address, then it is a function.
So, the correct statement is:
The relation (house, complete mailing address) is a function, but the relation (complete mailing address, house) is not.