Religion is neccessary for humans, because it helps us understand on where we came from, and who created us. Religion is the reason we have unity, it is our guide in all our actions. People preach us to be a person with responsibility. So religion is neccessary for all people.
Science also explains the world but with evidence. It disproves religion which has no basis other than a bunch of people having their own creative ideas and writing them down in a book to try and understand the world ~2000 years ago, and survives to this day because the followers are influenced by others.
Religion is necessary for humans to know not only where did we come from but for to whom do we believe. Religion is where we believe since we were a child until we die. Since we were born, all of us have a religion to us to know to whom do we follow. Our religion is the one who will guide us in what is our beliefs. Different Religions is being spread to other country if they were colonize by other country.