which religion is widely spread in the world?

Short, sweet, and to the point answer: You're wrong. The world is about 1/3 Christian, and 1/5 Muslim: Sources http://www.adherents.com/Religions_By_Adherents.html https://www.cia.gov/library/publications/the-world-factbook/print/xx.html

I dont know whether i am right or wrong but Buddhists are present more in this world. Also these days many people are getting converted to christanity with missionaries spreading the gospel. Muslims i believe occupy second place the first being buddhists.

Last I saw the number of christians worldwide WAS declining but only slightly. Islam is the one of the world's major religions though, yes, it's right up there with christianity. Paganism is creeping up on both of them as a growing religion worldwide, last I looked also though.

i think christians is the majority in the world, and muslims is the second. but the number is nothing to do with the quality. the huge number of followers (christians and muslims) doesn't always represent the the two religions are better than other religions in term of philosophy, the quality of the followers etc.

No Christibity is still the largest, but islam is the fastest growing

The majority of people are definitly muslim, then comes christianity. The thing is many countries containing A LOT of people are muslim, which really brings that number up. On the other hand if we look at the places were the religions are practiced (in majority), we would probably see a bigger part of the map took up by christianity, not sure