Inverse of dependency

In a project management context where A and B would be tasks, if A needs B, then B is a dependency of A. Is there a word to describe what A is to B?

As @KateGregory put it, I want to replace "we need to get B done, a lot of things are depending on it" to "we need to get B done, it has a lot of X" where X is the word I'm looking for.

I'm talking about the English concept, not the logical implication, though they're clearly related. Predecessor / successor is not what I'm looking for.

As discussed here: The dependent depends on the dependency.

we need to get B done, it has a lot of dependents.

Here are some more phrases which mean the same as each other:

A (the dependent) depends on B (the dependency)
A requires B
A is made available by B
A is an opportunity from B

B is a prerequisite of A
B blocks A
B allows A