Question

question 22 (1 point)
a bus driving through the desert in arizona breaks down. after walking three hours in the hot sun, which person(s) described below makes (make) the appropriate choice(s) to restore body fluid volume?
i. reabsorbing more water
ii. excreting more water
iii. excreting more salt to make water more isotonic
iv. reabsorbing more salt so that water follows
i only
i and iv only
ii and iii only
i, ii and iii only
i, ii and iv only
question 23 (1 point)
following an action potential, during which period is the neuronal membrane incapable of responding to another stimulus?
threshold potential
action potential
resting potential
refractory period
depolarization

Explanation:

For Question 22: When the body is dehydrated (after walking in the sun for three hours), the kidneys need to conserve water. Reabsorbing more water (I) helps retain fluid. Reabsorbing more salt (IV) creates an osmotic gradient that causes water to follow (due to osmosis), also helping in fluid retention. Excreting more water (II) would worsen dehydration. Excreting more salt (III) would not directly restore body fluid volume as effectively as re - absorption mechanisms.

For Question 23: The refractory period is the time after an action potential when the neuronal membrane is less likely or incapable of responding to another stimulus. The threshold potential is the level of depolarization needed to trigger an action potential. The action potential is the electrical signal itself. The resting potential is the normal state of the neuron when not firing. Depolarization is a phase in the action potential generation.

Answer:

Question 22: I and IV only
Question 23: refractory period