Review some of this information on Coronavirus (COVID-19) from the CDC (Centers for Disease Control and Prevention) and IDPH (Illinois Department of Public Health) webpages:

https://www.cdc.gov/coronavirus/2019-nCoV/index.html

http://dph.illinois.gov/covid19

in 300 words or less, answer the following question in essay format while using APA citations and references. 

1. List all descriptive observational study designs and state three ways in which they are different. 

a. Which design is most used now to identify new covid cases?