Resolution:
- 1) He can build nesting boxes, can't he? (Positive statement, negative tag with the same auxiliary verb 'can').
- 2) All energy originally comes from the sun, doesn't it? (Positive statement, negative tag using 'do/does' as the auxiliary verb since 'comes' is in the simple present).
- 3) You're a member of the Eco-club, aren't you? (Positive statement, negative tag with the same auxiliary verb 'are').
- 4) You haven't read a book about ecology, have you? (Negative statement, positive tag with the same auxiliary verb 'have').
- 5) Dave is recycling cans, isn't he? (Positive statement, negative tag with the same auxiliary verb 'is').
Final Answer: can't he, doesn't it, aren't you, have you, isn't he