Well it depends how you interpret this.

Humans without science at all level would die before 35 average, so Science can more than double the life expectancy and quality of life.

Religion can give peace of mind.

Now when badly used, religion can make conflicts and a lot of killing, but only with the power of the science we can destroy the world...

So religion even when properly used is a threat, but when abused only science can really make a killing.

They both can be harmful to humanity if not used right.

Capitalism is worst threat to humanity.

Science is the main reason your typing this question on a computer, so it's not to be taken for granted how far it has advanced humanity.

The weapons and stuff are made through mankind's undying urge to kill/destroy each other.

Religion on the other hand, religion has it issued, but nothing else teaches peopls morals, caring about the less fortunate, etc and nearly all laws are based on religious text, so one is to wonder if humanity would have advanced this far with out it.

Long story short, the problem no matter how you slice it comes back to violent people, not religion or science, but conflict and violence seems to be deep in our overall genetic code, so who knows if humanity will ever shake it.

They are both a double edged sword. The right people will used it for good the wrong for bad.

Science since its responsible for the industrialisation of our world and the consumption society we live in. Which will be eventually our downfall, just a matter of time. Also without any 19 and 20th century science war could never destroyed the planet. Just a matter of time before the third world war for water and arable grounds and nutrients will start, with out linear production cycle an ever growing population of humans and humanity's gigantic urge to destroy their own environment (like every other  oppuetnustic species though). And if that doesn't destroy us I doubt humanity is strong enough to live trough a new ice age. He'll most of us including me couldnt live three days without electricity.

You should check how well the Soviet union cared for its environment or China for that matter. Pollution is not exclusively linked to capitalism.

Religion is more dangerous by far because it's an irrational belief system and it's based on "personal experience" or "their truth" rather than what they can prove. If they believe that you're the devil or that a war is justified then it's alot harder to get them to back off. You'll more than likely have to break the back of their religion or wipe them out to stop their war.

Science is dangerous in the sense that it brings about a change whether you're ready for it or not. it introduces new things that can change the world in various ways. It's more or less a tool though and what happens depends on who's at the helm or how people react to it.

This thread has nothing to do with that. 

If they are the reason humanity is put back to a primitive state it won’t be just one of them that is the reason. It will be tha religious views causes science to put an end to us all.