Weight of air
Depending on elevation, the air pressure
varies. This is because of the weight of the air that is exerting pressure on
earth. At higher elevation, there is less layer of air that is exerting pressure
so the atmospheric pressure is also less. At lower altitudes or at sea level,
more layer of air is exerting pressure so the atmospheric pressure is also
more. The sun’s energy has nothing to do with air pressure. The energy that the
Earth gets from the sun is more or less constant. The same with density of
nitrogen, and the earth’s magnetic field, they have nothing to do with air
pressure.
The cytoplasm in a single-celled organism and the circulatory system in a human both transport substances throughout the organism
Answer: The answers seem correct.
1. Active transport - the process in which energy is used to move the particles of a substance against a concentration gradient from a region where they are in lower concentration to a region whey are in higher concentration.
2. The answer chosen for #2 makes sense because energy is usually needed when you putting effort into doing an activity that includes some type of force. That means ions are using energy to be moved against the concentration gradient.
3. Volume makes sense for the last question since the cells are using a space (volume) to move material in and out by diffusion. The other options besides volume are unreasonable.
DNA gets compact only during cell division and are called chromosomes. On other conditons, it forms a network of thin threads called chromatin network.
Another difference would be that DNA contains the 5 carbon sugar deoxyribose while RNA usually contains the 5 carbon sugar of ribose. One differs from the other, as ribose has an additional hydroxyl group bonded to one of the carbon atoms, where as deoxyribose does not.
