The correct option is B Habitat loss and fragmentation
Our planet Earth is endowed with enormous and rich biodiversity (a variety of life forms). But unfortunately, this biological wealth is rapidly declining due to human activities.
There are four major causes for the accelerated rates of species extinctions. These four major causes are often referred to as 'Evil Quartet'.
These include habitat loss and fragmentation, over-exploitation, alien species invasions and co-extinction.
Habitat loss and fragmentation - This is the most important cause of loss of biodiversity.
There is a huge habitat loss in the tropical rain forests. These forests which once covered more than 14 percent of the earth’s land surface, now cover no more than 6 per cent.
The destruction of these forests is happening at a very fast rate.
The Amazon rainforest (‘lungs of the planet’) is home to millions of species. It is highly unfortunate that these forests are cleared for cultivating soybeans or getting converted to grasslands for raising beef cattle.
Destruction of such large habitats leads to fragmentation. Birds (especially migratory birds) and mammals that require large territories are affected by fragmentation of large habitats.