What is histology? Why is it important to know the function(s) of different
tissues?

histology is the study of how tissues are structured and how they work. knowing what a normal tissue looks like a d how it normally works is important for recognising different diseases. it also helps in figuring out what causes certain diseases, how to treat those diseases, and whether the treatment has worked.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.