Stem cells have the capacity to regenerate, and some can even regenerate into almost any type of cell. stem cell research is a relatively new science that can be used to recreate organs such as livers or that would give many terminally ill people a chance to survive. what is one disadvantage of stem cell research?
a. the long-term effects of stem cells are completely unknown.
b. invasive surgery is required to extract organs grown with stem cells.
c. we cannot control which organs stem cells will develop into.
d. stem cells have no practical application to regenerative medicine.

My guess would be A. B isnt right because you dont need a whole organ to grow an organ, but just a few of its cells. C isnt good either because you can control what stem cells will develop into by taking a cell from whatever is need, and d just doesnt make sense to me.

Stem cells have the ability to become other cells and also tissues. These functions occur after cell division after a long period of. Research has been done to determine the effect of stem cells. Stems have not been used for a long period of time for research to determine what will happen after a long period of time and to analyze it. The disadvantage is long-term effect of the stems being completely unknown. Once trials have been demonstrated for the stems for a long period of time, this disadvantage will be erased. 

Lipid because of the high percentage of carbon to carbon bonds, which store more energy than other bonds.

Answer:

it provides an alternative energy pathway for the reaction to proceed.

explanation:

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.