Copolymers are classified into four subgroups: ______ 、 ______、 ______ 、 ______ according to the ordered degree of molecular arrangement.
The Molecular Genealogy Research Group is building a database for the purpose of______
A.offering assistance in working out genealogy-related problems
B.solving many issues without relying on traditional written records
C.providing a pedigree chart of at least four generations in the world
D.confirming the assumption that all individuals are of the same origin