Answer: When the plant has enough water in its cells the guard cells swell up and open the stomata. When the plant isn't getting enough water the guard cells can't swell and the stomata stay closed, so the plant doen's lose water. But if the stomata are closed photosynthesis can't happen and eventually the plant might starve.
Explanation:
It would be A. That’s the point of a flu shot. U inject the virus to make your body know it’s bad and when It comes along again to fight it hard.
If the stimulus frequency is so high that the relaxation phase disappears completely, contractions become continuous in a process called complete tetanus.
What is tetanic contraction?
- When the motor neuron that innervates a skeletal muscle generates action potentials at an extremely rapid rate, a persistent muscular contraction known as a tetanic contraction is induced.
- A motor unit has experienced its motor neuron's maximum stimulation during this state, which lasts for a while. This happens when several impulses with a high enough frequency excite the motor unit of a muscle.
- Every trigger results in a twitch. A slow enough stimulus delivery will cause the muscular tension to release between each succeeding twitch. High frequency stimulation will cause the twitches to overlap, which will cause tetanic contraction.
Learn more about the Nervous system with the help of the following link:
brainly.com/question/3239081
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