Answer:
Sorry I'm not sure on questions 11-20 but I thought I'd answer a few since you need the answers.
21. PC
22. CC
23. PC
24. CC
25. CC
Explanation:
21 is a PC because the pencil is not changing it's form. 22 is a CC because when you're frying an egg the egg goes through a chemical change and changes form. 23 is a PC because the paper isn't being chemically changed. 24 is a CC because the ingredients in the cake and the cake itself is going through a chemical change. 25 is a CC because anything with fire is a chemical change, it is forming a new substance, and it's producing heat.
