Answer:
Explanation:Selectively permeable means a membrane allows the passage of some molecules or ions and inhibits the passage of others. The capacity to filter molecular transport in this manner is called selective permeability
Answer:
Negative Feedback
Explanation:
Negative feedback is a stimulus that cause the system to move in the opposite direction of what has happening. For example if your are cold, you will shiver in order to create heat that will cause your body temperature to increase. But if you are hot you will sweat which will cause your body temperature to decrease.
Answer:
The frequency of the sound.Hope this helps btw
Explanation:
You would need to know how fast the sound waves go through the air.
sitting in a chair getting hit with a reflex hammer in the knee
