It is useful for an ecologist to identify the keystone species in an ecosystem because the keystone species is important to maintaining the stability of an ecosystem, and any changes in the keystone species population shows that there is changes in ecosystem health.
Answer: B and D
Explanation: We can break down why the correct answers are choices B and D by understanding why A and C are incorrect.
Option A states that active transport utilizes channel proteins, and facilitated diffusion utilizes carrier proteins. This is incorrect. Active transport involves carrier proteins, and facilitated diffusion involves channel proteins. Carrier proteins are different from channel proteins in that, while channel proteins can only facilitate the passive diffusion of ions into or out of the cell along their concentration gradient, carrier proteins can also use ATP to move ions in or out of the cell against their concentration gradient.
This brings us to why option C is also incorrect. Option C states that both processes require the input of energy in the form of ATP. While active transport requires the use of ATP to transport ions with or against their concentration gradient, facilitated diffusion does not. This is easily remembered when we consider that active transport is called *active* transport because the cell is *actively* using energy to transport ions.
Hope this helped.
Rock moves outward, A crack forms, Magma pushes upward, Magma hardens
Clinical death is the medical term for cessation of blood circulation and breathing, the two necessary criteria to sustain human and many other organisms' lives.
It occurs when the heart stops beating in a regular rhythm, a condition called cardiac arrest.
Brain injuries start to accumulate almost immediately after Clinical Death.
Full recovery of the brain after more than 3 minutes of clinical death at normal body temperature is rare.
Usually brain damage or later brain death results after longer intervals of clinical death even if the heart is restarted and blood circulation is successfully restored.
Although loss of function is almost immediate, there is no specific duration of clinical death at which the non-functioning brain clearly dies.
The most vulnerable cells in the brain, CA1 neurons of the hippocampus, are fatally injured by as little as 10 minutes without oxygen.
However, the injured cells do not actually die until hours after resuscitation.
Brain failure after clinical death is now known to be due to a complex series of processes called Reperfusion Iinjury that occur after blood circulation has been restored, especially processes that interfere with blood circulation during the recovery period.
Hope this helps!!!
~Alkka♥
