Lower Control Arm w Hub vs. Bearing

Difference is one, the tire can come off lower control arm,second the hub can just just lock

But does my car have a wheel bearing? Or does it have a control arm and hub instead?

Hub yes has bearings the best way to check is to jack up the car and try wiggling the tire if it moving like it wants to come off than that's ur problem

A lower control arm and a hub bearing is two different items the whirring noise you hear is most likely the hub bearing and sometimes a bearing makes noise and the tire is still tight for them to want to replace the control arm ask them to show you how bad it is before having them replace it. Is your steering wheel straight or does vehicle pull to one side if you let go of steering wheel while going straight ?

My car pulls to the left and when I break, the steering wheel shakes and clunks. Thanks

I guess what I am trying to understand most is this. On my cat specifically, is there a hub bearing AND a wheel bearing or is it an either or kind of thing?

That sounds more like a seizing up caliper or collapsing brake hose and the shaking is the the rotor is warped from the bad caliper or hose. Just hub bearing not wheel bearings.