recruitment and selection

Job analysis is finding out what's in a job. That will then from the job description. Open: How do you deal with tight deadlines? [Should produce a long descriptive answer] Closed: Can you deal with tight deadlines? [Will result in a 'Yes' or a 'No'. Presumably only a fool would say 'No' in a job interview] Problem solving question: Tell me about a time when you had a tight deadline and how you handled it. [A variant of an open question] Leading question: This job often requires week-end working. Will you be able to do that? [The expected answer is made clear in the question. A more neutral question would be 'Can you work at weekends?]

What is meant by succession plan?

It is who should replace senior people when they leave. For example, it was known for some time within the company that Steve Jobs of Apple had a terminal illness. The company would have thought carefully about who should take over (Tim Cook) so that investors, suppliers and customers maintained their confidence in the company. Similarly with executives coming up to retirement.

Dear sir, Could you briefly explain what's the difference between skills and competence?

I've said before, for generic questions on terminology, look at Google. More question like this will simply be deleted.