https://www.webmd.com/osteoarthritis/news/20060505/patients-rate-knee-hip-replacement?src=RSS_BLOGGER#1 

 Every unit will contain web sites that will expand the information you will have available on the subject. You will be expected to visit one or more of these web sites and submit an essay in the essay assignment about the information in the website. Complete this assignment by writing a 2 paragraph essay (not less than 120 words) about something you learned from one or more of the web sites. Enter the essay in the submission box and submit it.