Religion has always played a key role in art expression. how do you think it has changed from primitive times through the renaissance, to today?

Religion was and will always be a big part in art, because lots of people base their whole lives around religion. In the Renaissance religion played in gigantic role. Leonardo Da Vinci painted 'The Last Supper,' while Michelangelo painted the Sistine Chapel ceiling and 'The Creation of Adam'. These only name a few, but these paintings still stand out as some of the most memorable art in history. Today art is more expression about the human body and emotions, unlike how back then it was focusing on religion. 

Art has often centered itself around societal belief systems and the aesthetic of the times. Taking on a eurocentric point of view in this answer; in medieval ages, societies ran on superstition and the power of religious authorities, and the art of the time reflected that as the majority of art created were of deities. After the Age of Enlightenment and the romantic movement, rationalism and realism swept the artistic world. Here, religious powers were represented less as artists and writers began focusing more and more on the tangible and the transcription of real life. In the Post-Modern era, where we are now, religious works don't often come from a place of worship anymore. They have become more of a platform for debate, discussion, and acceptance conveyed through visual work.

Its not wavy i took it so it might be  thick  hope it

Very true. in today’s age anything is possible.