Answer: digestive is the correct answer
So we know that to transport materials in or out of the cell, we need to have access to both the inside and outside of the cell. This would require that the protein be a transmembrane protein that reaches both the inside and the outside of the cell.
So in this case, let's look at pore proteins. These are proteins that cross a membrane and act as a pore for the materials that need to cross the membrane.
One example of a pore protein is an aquaporin. These proteins aid in the transport of water into or out of a cell.
Therefore, the answer to your question is: A) Pore proteins.
The awnser is the last one
<span><span>Clouds of gas form within galaxies.
</span><span>Formation of structure within the gas clouds, due to "turbulence" and activity of new stars.
</span><span>Random turbulent processes lead to regions dense enough to collapse under their own weight, in spite of a hostile environment.
</span><span>As blob collapses, a disk forms, with growing "protostar" at the center.
</span><span>At the same time, bipolar outflows from forming star/disk system begin.
</span><span>Material is processed, moving in from the blob to the disk. What is not lost in the outflow builds up on the protostar.
</span><span>When the protostar begins to undergo fusion, it becomes a real star.
</span><span>Once the outflow ceases and the "accretion" phase that lead to the buildup of the star ends, a disk of "leftover" material is left around the star.
</span><span>At or near the end of the star-formation process, the remaining material in the "circumstellar disk" (a.k.a. "protoplanetary disk") forms a variety of planets.
</span><span>Eventually, all that is left behind is a new star, perhaps some planets, and a disk of left-over ground-up solids, visible as a "Debris Disk"around stars other than the Sun, and known as the "Zodaical Dust Disk" around the Sun.</span></span>
