What problem is solved by the linnaean system of classification

Due to the linneaus system of classification scientist were able to identify  organism name , group via standardized system . They have found similarities  in the organism  like DNA / RNA ( genetic composition), embryonic development  etc . so that they can study a organism completely . With the help of this system of classification  scientist were able to give a particular name to a organism which is standardrized in the whole universe. It makes easier to all to identify an organism , otherwise different places have different name for a particular species.

d. the weight of the book

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.