As I, and many others have said, without religion, there's a chance none of this would be needed to be asked.
Do you think there would be no wars, terrorists or conflicts if there was no religion? I think this is unlikely. Humans would still form groups and ideologies, and some of these would be negative. They'd also still fight over resources and territory.
Most wars in human history have not been caused by religion.
For the report Five Key Questions Answered on the Link between Peace and Religion by the Institute for Economics and Peace, researchers looked at all the wars in 2013, and found no "general causal relationship" between religion and conflict. The study found that
"There is no clear statistical relationship between either the presence or the absence of religious belief and conflict." and
"Factors other than religious differences are more significant in determining the levels of peace. These factors are corruption, political terror, gender and economic inequality as well as political instability."
Also
"Countries with greater religious freedoms are generally more peaceful" and "The most influential factor affecting religious freedom is the government type. Full democracies are the most peaceful and have the greatest level of religious freedom, regardless of the type of religious belief or various religious characteristics."
The above research is also referred to in this Huffington Post article:
"The Institute for Economics and Peace report also found that having less religion in a country doesn’t make it more peaceful. The proportion of atheists in a country had no bearing on levels of peace."
"Countries with the highest levels of atheism – mainly communist or former communist states like Russia and the Czech Republic – were not necessarily the most peaceful. North Korea, which has one of the lowest rates of people practising religion, was one of ten 'least peaceful' countries in world last year, according to the report."
The Huffington Post article also says
"The Encyclopedia of Wars, an extensive study published in 2008, chronicles 1,763 wars throughout human history. It names just 123 as 'religious in nature' – a little under 7%."