Complete the summary using the list of words below. Choose the correct word and move it into the gap.

Phylogenetic analysis of Little Red Riding Hood

Tehrani used techniques from evolutionary biology to find out if [1] existed among 58 stories from around the world. He also wanted to know which aspects of the stories had fewest [2], as he believed these aspects would be the most important ones. Contrary to other beliefs, he found that some [3] that were included in a story tended to change over time, and that the middle of a story seemed no more important than the other parts. He was also surprised that parts of a story which seemed to provide some sort of [4] were unimportant. The aspect that he found most important in a story’s survival was [5].