Which is the central idea to keep in mind for interviews? 1.- Preparation and physical appearance are key
2.- Everything will work out if you are prepared
3.-Wear clothing and statements that help you stand out
4.- Be friendly and show them your personality

1. Preparation and physical appearance are key.

Explanation:

There are several things such as being friendly and polite, paying attention to body language etc that one has to keep in mind when preparing for interviews, yet preparation and physical appearance is the key because when one dresses properly and his fully prepared, other areas will be fine.

Preparation involves knowing the right time to arrive at the interview venue, practise possible questions that might be asked, make extensive research about the organization,review your qualifications against the role you're being interviewed for etc.

Wearing clothing and statements that helps one standout are secondary ideas. The statement 'everything will work out fine if you are well prepared' is also secondary because I may be well prepared but my physical appearance may not be appealing hence not a central idea of preparing for interviews.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link :

answer; ///(d); determining who competes most closely   with whom evaluating whether industry driving forces and competitive pressure favor some strategic groups and hurt others, and ascertaining whether the profit potential of different strategic groups varies due to the strengths and weaknesses in each groups respective market positions;