Vectors used in recombinant DNA technology

Vectors used in recombinant DNA technology
  A. are self-replicating forms of DNA carriers.
  B. are always circular DNA molecules.
  C. deliver DNA to cells for replication.
  D. are self-replicating forms of DNA carriers and deliver DNA to cells for replication.
  E. are always circular DNA molecules and deliver DNA to cells for replication.

Question 2

Embryo splitting
  A. mimics the way identical twins and triplets are produced naturally.
  B. is a means of cloning animal embryos.
  C. requires in vitro fertilization.
  D. is a technology that could improve the production of domestic animals.
  E. is characterized by all of these traits.