It is irrefutable that
THE world of early centuries was
A better place to live than today's modern world
. Many arguments surround my opinion. - this makes no sense at all. How about try this- This can be exemplified through the pollution that is currently plaguing our planet.
First of all today whole world is heading towardthe doom because of the dire Global Warning (lowercase- global warming, not Global Warming) problem.
- WE DO NOT REALLY KNOW IF THERE IS GLOBAL WARMING YET SO I SUGGEST THAT YOU DON'T PUT THAT. IT IS VERY CONTROVERSIAL. If you want to put it there, then you have to back it up with evidence, but it is not proven yet.
An Increasing population and pollution are the main reason behind this situation.
To put in the nutshell,- wrong idiom.
In a nutshell is correct.
There are a lot more mistakes, so revise and then I will help you more.