I'm almost positive it's non of the above. If I'm not mistaken the Spaniards were against slavery.
Yes i think it is a good idea because it has to.
The answer is: Expert
Expert testimony is a form of testimony that come from people who have deep knowledge and experience in a certain issue. This type of testimony usually regarded very highly in the court and has higher chance to convince the juries to a certain opinion.
(examples of expert testimony are: testimony regarding fake internet account from IT experts, testimony about violent behavior from psychologists, etc)
The agency that distributes blood is : World health organization
The world Health Organizations existed to solve various problems concerning the health of humanities.
Distribution of blood will helped various problems such as blood transfusion or sampling to create a vaccine
hope this helps