Known as the cell’s “command center,” the nucleus is a large organelle that stores the cell’s DNA (deoxyribonucleic acid). The nucleus controls all of the cell’s activities, such as growth and metabolism, using the DNA’s genetic information. Within the nucleus is a smaller structure called the nucleolus, which houses the RNA (ribonucleic acid). RNA helps convey the DNA’s orders to the rest of the cell and serves as a template for protein synthesis.
The answer is <span>c. Cold and flu season occurs when the weather is cold, so there must be a connection.
Even though choices a. and b. could make sense, nothing in Joel's research implies the connection between the choices and cold. Therefore, this leaves choice c. as the right one. If cold and flu season occurs</span><span> when the weather is cold, there must be a connection between cold and cold weather.</span>
If a red blood cell is placed in a hypertonic solution, the cell would shrink.
Hypertonic solution means that the solution has a lower water potential than the other side (which is the cell's cytoplasm in this case), and by that, water molecules would have a tendency to flow from a region of higher water potential to a region of lower water potential. This movement of water molecules is called osmosis. But note that a semi-permeable membrane (a membrane which can decide what substances can go in and out, the cell membrane is an example) has to be present in osmosis, or else the movement may be regarded as diffusion.
As the water molecules flowed away from the red blood cell cytoplasm, the cell loss so much water that the membrane has nothing much to hold and thus the cell shrinks.
