16. Which of the following statements best describes a clone?

A. An artificial life form
B. An offspring where all of the genetic material in every cell is identical to that of both parents
C. An offspring where all of the genetic material in every cell is identical to that of one of its parents
D. A type of sheep

17. In transgenic fish, the genes are introduced by

A. microinjection in fish
B. viruses
C. transfer of whole nuclei
D. all of these

18. Production of transgenic animals require transfections of

A. eggs or embryos
B. stem cells
C. red blood cells
D. all of these

19. Which of the following statement is correct?

A. Variation is caused by genes
B. Variation is caused by the environment
C. Variation can be caused by both genes and the environment
D. None of the above

20. Which of the following gene have been introduced into the transgenic fish?

A. Human or rat gene for growth hormone
B. Chicken gene for delta crystalline protein
C. E. coli gene for β-galactosidase
D. All of the above