Answer:
(a) an aquaporin
Explanation:
An aquaporin is a water channel which forms a pore in the cell membrane and facilitates the movement of water. Aquaporin is an integral membrane protein (permanently attached to the membrane) that enables the in and out flow of the water. This channel also prevents the passage of ions and other solutes, so it cannot change the voltage. There are four types of aquaporins, and they are mostly found in the kidney with the function of water reabsorption.
A population is essentially just a collection of all living things in one category. People are one population, insects are another, etc. Communities are "more organized" populations. Soccer players hang out with soccer players, spiders hang out with spiders. We split into "our people" within our population.
I know that may be a little confusing, but if you have anymore questions feel free to ask. I hope I was able to help. Best of luck!
It is due to agitation of the heart. This is the result of a blow in the area directly over the heart.
I remember the secondary structure by visualizing it. Understand that primary structure is just the order of the amino acids. The tertiary structure is the 3dimensional configuration of the whole protein molecule with multiple interactions guiding its fold (disulfide bonds, ionic interactions, hydrogen bonds, van der walls). Secondary structure is a step towards the conformation of the protein where it is made up of either alpha-helices or beta-pleated sheets. The alpha helices look like a spiraling staircase while the beta-pleated sheets look like a repetition of long loops. These two structures hold itself by hydrogen bonds.
