So why?
1. Like the rest answered, it's pretty much to check if you have a relative/ family working within the same organization (for some reason, chances are slightly higher when it's true).

It doesn't really matter. I believe most of the other applicants' answer are "No" as well. Nothing to worry about~ I wouldn't choose a company where I have a relative/ family member working there. No specific reason, just don't feel like it.

2. You can honestly admit that you're not good with this technical side of it. But, you can stress it like this: I'm not good with xxx but I'm better with yyy... etc etc and I'm willing to learn all aspect of xxx that I'm not familiar with.

Willing to learn is a good trait. One reason employers like to hire fresh grad (apart from cheap labour) is that they are easier to 'mould'.

It depends. Some ppl have lots of questions while others have none. Although the complany explained their operations, nature of biz etc etc, they might have missed out what's your main responsibility in the company. Surely you've read some of them on the job posting but when the interviewer explains it to you, you'll get a better picture.

Usually I would ask, "May I know what's my job scope/ task for this position?" it's more like asking, "what do I do in your company?" and I would also ask about the pay if the interviewer did not bring it up. Lastly, I would check with him/ her what sort of career advancement and benefits the company offers.

Lastly, you can always use the opportunity posed by this question. For example, say you need to provide 2-3months notification (instead of the usual 1 month), so it's best to bring it up when this question is raised. That's just an example. You might have other concerns and you can use it to enquire further.

When you ask more, it shows that you're somewhat more enthusiastic and interested in the company. Just my POV.