Answer:
nitrogen that cannot be used
In my opinion mixed layers would be the best choice
the only reason i am wasting one of the two answers your post is allowed to get is because its been 3 hours and no one has answered yet.
Where do you go to school? I think it is very coincidental that you have the exact same question i do, and you had the question exactly when I got the question...about 3 hours ago. Now it IS a curriculum so its not that weird, but by any chance are you in K12? 8th grade?
Answer:
1. Either porifera or asymmetrical
2. Invertebrate
3. filtering
4. Axis
5. I don't know this one, I'm sorry.
6. Exoskeleton
7. Cold-Blooded creature
8. Vertebrate
9. Endoskeleton
10. Warm-blooded animal
Good Luck! Hope I wasn't too late.