According to the passage, human activity has had which of the following effects on salmon populations?
A. An increase in the size of salmon populations in some previously polluted rivers
B. A decline in the number of salmon in some rivers
In first para author says that the numbers have reduced and at some places specieis became extinct
C. A decrease in the number straying salmon in some rivers
D. A decrease in the gene flow between salmon populations that spawn in polluted streams and populations that spawn in pristine streams
Human activity caused salmons to spawn in other pristine stream and so they mix with existing salmons in that area and gene flow increases. So choice D is wrong
E. A decline in the vulnerability of some salmon populations to the effects of naturally occurring habitat destruction
anirudhbhalotia wrote:Why is D not the answer for Q.11.
In the passage its mentioned-
Such a dra-
(75) matic increase in straying from
damaged areas to more pristine
streams results in substantial
gene flow, which can in turn lower
the overall fitness of subsequent
generations.
Some explanation would be helpful. Thx.
