What does it mean that form follows structure?

I had to do the same paper not that long ago, and I aced it! Form follows function means you explain the form, i.e what it looks like, its form basically, and then describe its function. My teacher really like it when I explained how the function has to do with the form. Like depending on its form it has a certain function. drawing and properly labeling diagrams will also give you bonus points if it is all ready not part of the project. Water is not as complex of a topic, but because of that it will be harder to write more. I would chose carbs. because you can write more about it, and your teacher will see you didn't just take the easy way out. I can't really help you with the exact details of the form and function because there are different kinds of carbohydrates, each with its own form, or structure, and and function. Your book should have all of the answers though. And know the answer well because most likely your teacher will put this question as an essay question on your next test. And I highly recommend writing how the structure of the cell contributes to the job. So basically how the form follows the function. lol!
Good Luck!
I Hope This Helps :D 

The answer is  a.first and third quarters