State whether the indicated angle pairs are adjacent or not. An explanation would be nice, but you don't have to.

1. Yes, angles a and b have a common vertex (starting point) and a common side (the line between angle a and b). They do not overlap.
2. No, angles a and b share a common vertex but not a common side.
3. No. Same as above.
4. Yes, anlges a and b share a common vertex and side.