If something poses a problem or a danger, it is the cause of that problem or danger.
e.g. This could pose a threat to jobs in the coal industry...
e.g. His ill health poses serious problems for the future.
If you pose a question, you ask it. If you pose an issue that needs considering, you mention the issue.
e.g. When I finally posed the question, 'Why?' he merely shrugged.
e.g. ...the moral issues posed by new technologies.
If you pose as someone, you pretend to be that person in order to deceive people.
e.g. The team posed as drug dealers to trap the ringleaders.
If you pose for a photograph or painting, you stay in a particular position so that someone can photograph you or paint you.
e.g. Before going into their meeting the six foreign ministers posed for photographs.
You can say that people are posing when you think that they are behaving in an insincere or exaggerated way because they want to make a particular impression on other people.
e.g. He criticized them for dressing outrageously and posing pretentiously.
A pose is a particular way that you stand, sit, or lie, for example when you are being photographed or painted.
e.g. We have had several preliminary sittings in various poses.
A pose is an insincere or exaggerated way of behaving that is intended to make a particular impression on other people.
e.g. In many writers modesty is a pose, but in Ford it seems to have been genuine.