I think the possibility is very small, because bitcoin has a limited amount, and it is more likely that bitcoin will be used as an asset.

If this is meant for the trading activity, it's happening now..in the cryptocurrency exchange market, Bitcoin is the first coin to buy and sell.

I think, NO. The first legalized used for buying and selling transactions is precious metals, then physical money.
But this doesn't mean it will not happen. In the some countries, bitcoin can be used as a digital payment tool.

Of course, yes. People say crypto currency means bitcoin. Bitcoin seems to me to enter the first of all crypto-currencies in the life of each person, and only then other crypto-currencies

Without any iota of doubt, my answer is affirmative. with the popularity that bitcoin is gaining, it could well be that currency. For those that are keen on prophecies, the holy book talks about a new world order where there would be a central government and a currency that will be used by the entire world, made possible by having some numeric codes implanted into ones body. Revelation 13:11-18 (The Holy Bible).

I think american dollar is the world currency today, so that bitcoin cannot be the first one but bitcoin can be the next world currency because of the fact that it is famous, it is expensive and new.

It should be so, but simultaneously with the present restrictions imposed by the government. This thing seems unlikely to come true and will probably forever be hope, hope, and hope. But let it be rice has become porridge however we all still benefit from its presence, because this bitcoin we love can still use to seek advantages by making it as an alternative in investing.

I think Bitcoin wont become the first world bitcoin currency for buy and sell. it is now in the first place of crypto currencies.but overall everything nowadays bitcoin price  is not same like before and discreasing day by day.so bitcoin users number are coming into less number and so that the coin is going down to the market.now many people did not like the bitcoin.and do their
transaction or buy sell in etherium or others coins.Because of bitcoin low rating others are taking place and sattling themselves strongly.so undoubtly it is a negative thing for bitcoin.

Maybe this can happen when the currency become acceptable everywhere and country do not have problems about using it. Even it is not used widely now, it is possible accepted because many are pushing to bring it to market not only along the internet. Bitcoin for now is good to be an asset aside from gold that even the price is very volatile, when the price back to good we could gain good profit.

Yes of course the possibility of bitcoin will be the first currency in the world, if all countries have received it. But for now still not because bitcoin is still the stage of development, wait until the next few days whether it will happen? I think yes. 

I think it'll happen soon.   just it'll take a little time to get adopted in every country..  that's the goal of bitcoin now.. to be a worldwide currency