Change
Transition
noun, する verb
Change and transition mean change and transition! Nifty.
へんせん
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
1996年から2013年までのトップ日本語学習サイト20の変遷を見てみましょう。
Let’s look at the changes in the top 20 Japanese language learning sites between 1996 and 2013.