If its the title, 'on' can be capitalized to put emphasis. Else, there no such rule to capitalize it.
Yes, chapters are typically capitalized in a book.
Yes, "Book Fair" should be capitalized as it is a proper noun.
No, coral does not need to be capitalized.
The word evolution does not need to be capitalized.
Yes, the chapter on climate change in the book is properly capitalized.
yes, it should be capitalized
No.
No, it doesn't need to be capitalized.
No, it shouldn't be capitalized.
No, circa does not need to be capitalized.
No, kinetic energy doesn't need to be capitalized.
Yes, "Penguin" should be capitalized when referring to the animal or the book publishing company.