Answer:
Sometimes molecules cannot move through the cell membrane on their own. These molecules need special transport proteins to help them move across the membrane. Facilitated diffusion is the diffusion of substances with the help of transport proteins in the plasma membrane. These special proteins are called channel proteins or carrier proteins, and they are attached to the cell membrane. In fact, they go through the cell membrane, from the inside of the cell to the outside. Facilitated diffusion is used for molecules that cannot diffuse rapidly through cell membranes on their own, even when the molecules are moving from high to low concentration areas. An example is the sugar plants and animals use for energy, called glucose. Even though facilitated diffusion involves transport proteins, it is still passive transport because the solute is moving down the concentration gradient so it does not require the use of cellular energy.
The correct answer that would best complete the given statement above would be the first option. Coral reefs are built by a small organism called a polyp. The polyp creates the structure of the coral reef by building a CUP out of a calcium carbonate. The skeletons of these tiny corals s<span>ecreted by the lower portion of the polyp. Hope this answer helps.</span>
Answer:
main difference between freshwater and marine life is the habitat they come from in the wild. Freshwater fish live in streams, rivers and lakes that have salinity of less than 0.05 percent. Depending on the species, fish can survive in temperatures ranging from 5 and 24 degrees Celsius
Explanation:
Photosynthesis:
I - Water, Carbon dioxide, O - Sugar, Oxygen
Cellular Respiration:
I - Oxygen, Sugar O - Energy, Carbon Dioxide, Water