Hey there!
For number 5, we have to think about things that we break every day and that need to be broken easily. How about food? Every day, you eat food and because it breaks easily, your body is able to start the digestion process in the mouth with chewing.
For number 9, I'm sure you can relate when I say you would not want your cell phone or computer to break easily. They're very useful, hard to repair or replace, and cost a lot of money.
Hope this helps!