I'm not quite sure about what is meant by "uniting or polarity". But "How would you describe the main characteristics of the mind-body process?" Impermanence, Dukkha, not-self and dependent arising. So whether it means is it a unity or a polarity, are they the same or different? Perhaps that's what it means. I would say they are dependent on each other.
Polarity: okay, they arise dependent on each other, therefore according to Buddhism they cannot have independent existence without the other. At least that's my understanding; because they arise dependent on each other. For example, eye consciousness arises dependent on the body and a contact between the senses and their objects. So it arises dependent on these things.
But they're neither the same nor different. When we feel pain in the body, to be able to feel the pain there has to be a consciousness there to be able to feel it. So whether the feeling can exist independent of the mind, I would not think that that would be so. They arise dependent on each other. And because they arise dependent on each other, there is contact and there is the arising of feeling. All things arise dependent on each other according to the Buddha's teaching. And this is actually how we get to see what I'm going to be talking about this morning, Anatta, the "not-mine" characteristic.
The body depends on the Four Great Elements, and life depends on having consciousness of these four great elements and the contact of the senses. And everything that we think we are depends on other impermanent things. So by investigating into the dependent arising nature of things we start to see that all we consider ourselves to be is dependently arising due to other impermanent things.