Answer:
some advantages of top down is that you can start off from what you know and figure out what you need to complete it, advantages to bottom up is that you can make something new . if you are starting something from scratch and you dont know what the end goal might be you would use bottom up but if you already have an idea or the final product of what you want you would go the top down approach.
Explanation: just saying you shouldnt just copy and paste my response but rather pick out what you want to say and use this to complete what ever your working on. hope i helped :)