Angiosperms are flowering plants, so I'd say flowers and the parts of flowers are a pretty common characteristic.
organ system must be present
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.
Answer:
Secondary succession takes place where a disturbance did not eliminate all life and nutrients from the environment. ... Buried seeds can sprout shortly after the effects of the disturbance pass, and some may have greater success from reduced competition and reduced shading.
Explanation: