Read the article $$Understanding FDA Regulatory Requirements for Investigational New Drug Applications for Sponsor$-$InvestigatorsLinks to an external site.$$ by M$.$ E$.$ Blair Holbein. Address the following questions in whole sentences $[10$ points$]$: $$ What is the difference between an investigator and a sponsor? Who will need to file the IND under which circumstances? $$ Under which conditions is an IND not needed? How can this be best determined by the sponsor or investigator? $$ In addition to the FDA CDER, which other organization has to be informed of any protocol changes or safety concerns$/$reports$?$ Always provide references with your assignment submissions.