Answer:
The membrane is selectively permeable because substances do not cross it indiscriminately.
Explanation:
I think that the answer this question would have to be c
<span>A stem is one of two main structural axes of a vascular plant, the other being the root. The stem is normally divided into nodes and internodes. The nodes hold buds which grow into one or more leaves, conifer cones, roots, other stems, or flowers (inflorescences); the internodes distance one node from another.</span>
The highest point the medium rises to and a trough is the lowest point the medium sinks to.
