22. In a study of heart rate in ocean-diving birds, researchers harnessed 10 randomly sampled, wild-caught cormorants
to a laboratory contraption that monitored vital signs.
Each cormorant was subjected to six artificial “dives" over
the following week (one dive per day). A dive consisted of
rapidly immersing the head of the bird in water by tipping
the harness. In this way, a sample of 60 measurements of
heart rate in diving birds was obtained. Do these 60
measurements represent a random sample? Why or why not?
not?

what image you forgot to include it.

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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measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.