Neurons communicate with one another through the release of neurotransmitters that bind to channels on the postsynaptic neuron. this is analogous to a lock and a key. in this example the lock is the while the key is the neurotransmitter.

The answer is receptor.

Explanation:

Neurotransmitters are chemical molecules released by the neurons to bridge the gap between and to be able to communicate. This is a process in which one side of the communication is the source of the neurotransmitters and the other is the receptor which is often used as a lock-key example. Since the neurotransmitter is the component which bridges the gap and in a sense unlocks the door, it is the key. The receptor is the part affected by the neurotransmitter which means that is the lock part of this example.

I hope this answer helps.

hypoxemia refers to a below usual concentration of oxygen in the blood, mainly in the arteries. hypoxemia is an indication of an issue associated with circulation or breathing and may lead to various symptoms like shortness of breath.  

the condition is identified by determining the level of oxygen in the blood sample obtained from an artery. it can also be predicted by determining the oxygen saturation of the blood with the application of a pulse oximeter.  

the normal arterial oxygen is about 75 to 100 mm hg. the values underneath 60 mm hg is generally considered with the requirement for supplemental oxygen. the normal pulse oximeter readings generally range between 95 to 100 percent. the values under 90 percent are regarded as low.  

in the given case, the oxygen saturation is measured at 93 percent, hence, there is no need to administer oxygen, that is, one should withhold oxygen.