At present, scientists can determine the configuration of gene units or their relative positions or DNA sequences in a chromosome. How is this knowledge useful to us? 1. With its help the lineage of livestock can be known. 2. With its help the cause of all human diseases can be known. 3. With its help, disease-tolerant breeds of animals can be developed.

At present, scientists can determine the configuration of gene units o

1.	At present, scientists can determine the configuration of gene units or their relative positions or DNA sequences in a chromosome. How is this knowledge useful to us? 1. With its help the lineage of livestock can be known. 2. With its help the cause of all human diseases can be known. 3. With its help, disease-tolerant breeds of animals can be developed.
A.	1 and 2
B.	only 2
C.	1 and 3
D.	all these
Answer» E.