I Dont know srry mate next time maybe
The answer is color.
Hope this helps!! =D
I'll try to explain, because I've had tubes before. In fact, I still have them.
For me, tubes were put in because of too many ear infections, and excessive water in my ear. The tube helped drain the water out. You can see A picture I have in a file. The tubes can be put I believe in the ear drum. They're put there to help drain water that has trouble getting out on its own.
A mutualistic and A a decrease in the number of corals
They both contain a Nucleus, the part of the cell designed to dictate the cells operations.