Sarah observed that different kinds and amounts of fossils were present in a cliff behind her house. She wondered if changes in fossil content occurred from the top to the bottom of the cliff. She marked the cliff at five positions: 5, 10, 15, 20 and 25 meters from the top. She dug out and removed 1 bucket of soil from each of the positions and determined the kind and number of fossils in each sample. 1. What was the hypothesis? 2. What would be the Control group? ( hint: not in paragraph) 3. What is the experimental group? 4. What was deliberately changed? 5. What responded to the change?

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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blue stars have the highest surface temp

stellar distances are usually expressed in light-years

the measure of a star's brightness is called magnitude

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he movement of air through earth's or any planet's atmosphere is called wind, and the main cause of earth's winds is uneven heating by the sun. this uneven heating causes changes of atmospheric pressure, and winds blow from regions with high pressure to those with low pressure.

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