2. Be a skeptic. Always be on the look out for inconsistent inobjective incomprehensible repetitionary answers. Specially those that sound scholarly and reference a lot of authorities.

3. Let me not pretend to be wise enough to answer those on your list, nevertheless I am willing to take lumps for my answers.

The set of rules we use by default to address any new problem not encountered before.

Why do most of the religious groups tend to be fundamentalists?

Practicing-religionists tend to be fundamenalists because they need to conform to something and be true to something!

Why is there so much violence in the name of religion?

Because historically violence is a good way to expropriate some one else's property or to stop some one from complaining. One has to surround violence with religion in order to solve THE oldest human problem, why wont he do the same to me (my term analogy-prevention? Loyalty, religion, skin color, culture are some of the rationale of the violent analogy-preventers.

Does being religious mean going back in time?

Being fundamentalist certainly does.

Can one go to heaven by brutally terrorizing fellow human beings?

Posits heaven which I deny.

Why is Hindu religion so diverse?

Because we use the label Hindu on many diverse beliefs. It really matters not what the beliefs of so labelled aree, the real question only is whether majority of existing hindus consider the person a hindu..

Does it mean our forefathers were more tolerant, learned and liberal in their thinking.

Or perhaps more cowardly, backward, incapable, ...

Does going to temple, church, pagoda, agar or a mosque makes one more religious?

Depends on the agent you ask to - fudamentalist yes, me a bigger time waster, you don't know..

Does one have to believe in God to be religious?

Yes

Why are rituals performed?

Conformity (that is how it is done) temporal consistency (that is how it it was) moronic-complexity (that is the way to do it - Sir/lady moron), ...

Do rituals lead us to salvation?

Nope.

What does religion mean?
repeat of question !!!!!!

Why should we be religious?
How else will you tackle new scenarios?

Why is there some much hatred between various religious groups?
Because each thinks they are exclusively right and there is a grabbable common intersection.

Does any religion in the world command its followers to kill humane beings in the name of religion?
Unfortunately that is the interpretation of some of the Quran passages I posted. Historically church has been doing so to scientists., so I assume their religion told them so.

Why should there be so many different religions in this world?
why so many political parties in Israel?

May be it God's trick to keep human population at reasonable levels?
Or may be devil's trick for justifying a lot of expropriation and its consistent aftermath?

What would have been the population of the this earth had we not had so many religious was and campaigns?
About the same. Terror achieves little numerically by counting victims and much much more by scaring a lot lot of people.

Could God have achieved the same result by making Human Beings less fecund and less fertile?
No. There are drugs that will do so right now, but no positive effects.