I believe they cannot start with big trees and bushes because the there is not enough nutrients in the soil, so instead pioneer species pave the way for primary succession.
They are all eukaryotic, I hope this was the answer you were looking for :D
A: no
In barium examinations, you want to see if something it's obstructing, like the colon. You only use a front view.
B: yes
When you want to see if everything it's alright about the spine, you need to analyze the curvature, and for that, you need front and side view.
And, is the only radiographic tool that can be done in antero-posterior and lateral views.
C: no
When you are looking for trauma or bone breakage, you may need only a side view or front view.
D: yes
If you are looking for any trauma or emergency, you need different positions of the bone to discover any breakage.
When scientists measure, they use the metric system.
