Consider the following statements: I. The sentence “If y

Consider the following statements:
I. The sentence “If you want to improve, you need to practice” is an example of the zero-conditional structure, which is used to talk about something that is always true or always the consequence of something else. II.“They would be able to travel more if they didn’t have so many dogs” is an example of the first conditional, and it is used to talk about possibilities for the future, specially when they are likely to happen. III. “I wouldn’t have called if I knew you were studying” is an example of the third conditional, which is used with unreal hypothesis because it is about something in the past.
Which statements are correct?