I think the answer is oxygen, but not 100% sure
I’d say conical shape- coniferous trees are known for this shape.
<span>Single-ply membranes are a assorted
and promptly increasing group of sheet materials that are functional to the
roof in a single layer. As equated to built-up membranes, they need less
on-site labor, and they are usually more flexible and therefore less liable to
to cracking and ripping. They are attached to the roof surface by any of
several means.</span>
