<span>Stem cell research is being conducted for cancer, diabetes and spinal cord injuries. But stem cell research has not included bird flu, sometimes called avian influenza Bird flu is caused by a virus which are not effected by stem cells applications.</span>
The answer is B
Here is a small experiment you can do to test this.
<span>
Put a pot of water on the stove and bring it to a boil. Take a dry lid and cover it for a minute, and lift the lid up. What happens?
What should happen is that the water droplets run down the lid and fall back into the pot.</span>
When something needs to be transported against its concentration gradient, or a molecule is too big to simply diffuse through a membrane, active transport has to be used. So active transport requires energy (ATP).
Examples:
1. Antiport pumps: transport one substance in one direction while transporting another substance the other way. An example of this is the sodium-potassium pump.
2. Symport pumps - uses a substance that wants to move from an area of high concentration to low concentration and carries another substance against its concentration gradient. An example of this is the sodium-glucose transport protein
3. Endocytosis - large amounts of extra cellular fluid can be taken into a cell - needs ATP to bind proteins in the cell membrane and causes them to change their shape...which eventually causes the surrounding of the fluid to be brought in (a vesicle).
4.exocytosis - opposite of above
