Electric current is the flow of _ through a substance.

Electrons

Explanation:

A current is a flow of electrons for this to happen there must be a closed circuit.

- The electricity is nothing but a flow of free electrons present in the external surface of the electricity conducting substance.

The flow direction of this electron flow is also the direction of electricity flow.

- There is a type of electrical circuit which is known as the closed circuit. This circuit is completely connected with the two terminals of the battery and there are no hindrances in the path of electricity flow in these circuits. That's why current can only flow through these complete circuits.

compost can be added to topsoil as a:

pesticide

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.