Yes, that is exactly their purpose.
The purpose of a standard screwdriver is to turn screws so they go into or come out of the work.
The most common method is with one or more screws or nails. Wood screws are especially made for the purpose. But screws and nails are not the only option. They can be bolted or pinned together, for example. with a bolt
Eye screws allow something to be latched onto the round part, like a door latch or even a tie-down cord.
The purpose of a screwdriver is to tighten or loosen screws by applying rotational force to them. It is a tool commonly used in construction, woodworking, and mechanical work.
A screw driver is used to screw, screws into wood it is a very useful tool.
To attach things together.
The use of screw driver is to pull out and in the screws
You may have an air lock in the heater pipes some vehicles are fitted with bleed screws for this purpose.
Because it holds the screw straight while you insert it. There is also a 'split blade' screwdriver for this purpose.
I don't know where specifically they would be (if there are any at all...), but on most of the engines I have worked on that have had them, they were in the engine block somewhere, with the intended purpose of a drain, not an air bleed. I don't think many modern cars (if any at all) have bleeder screws for coolant.
Countersink and countersunk are the same meaning. Countersink is English word Countersunk is German word <><><><> Present tense, and past tense. "I need to counersink these screws." "These scews were countersunk" Countersink can also be a noun- name of the tool used for that purpose. "The screws were countersunk with a countersink."