Final answer:
No, w is not a subspace of the vector space because it is not closed under addition.
Step-by-step explanation:
No, w is not a subspace of the vector space. In order for a set to be a subspace, it must satisfy three properties: closure under addition, closure under scalar multiplication, and containing the zero vector. Option 2 states that w is not closed under addition, which means that there exist two nonnegative functions in w whose sum is not a nonnegative function. Therefore, w fails to meet the closure under addition property and cannot be a subspace.