Grading: students give correct answers, but in the wrong places
What is your purpose of a grade? If it is a numerical certification of their knowledge, full credit is the right choice, as they indeed have shown to know the answer to both questions. If the assignment didn't have time pressure, you may consider applying a small penalty for the not so good organisation, but be prepared to have it challenged.

Don't penalise adding extra, factually correct, information. Other professors welcome it, and even, the expect you to understand that the question has unwritten sub questions that should be answered too for the full credit (I had one of these in high school, and "give three examples of mammals" meant also "explain what they are and why are they mammals, or I will only give you half").

Lastly, if several students have made the same mistake, consider that maybe the questions are not clear. I must say I don't quite understand the difference from your excerpt.