The Russian species that became extinct in recent years is . . . . . . .

The population of marine fish is declining worldwide due to over-harvesting. This is an example of which of the following?

What is common to the species shown in figures $A$ and $B$?

$A$ weed belonging to the family $Asteraceae$ which has spread in all parts of India is

What are species that are likely to become extinct in the near future called?

The recent illegal introduction of the African catfish $Clarias$ $gariepinus$ for aquaculture purposes is posing a threat to the indigenous catfishes in our rivers.