The number of wildlife is continuously decreasing. What is the main reason for this?

Which of the following endangered animals is the source of the world's finest,lightest,warmest,and most expensive wool,known as Shahtoosh?

$A$ tree species in Mauritius failed to reproduce because of the extinction of a fruit-eating bird. Which one of the following was that bird?

Which of the following communities is more vulnerable to invasion by outside animals and plants?

Among 'The Evil Quartet',which one is considered the most important cause driving extinction of species?

How many of the following are causes of biodiversity losses $:-$
$(a)$ Habitat loss
$(b)$ Over-exploitation
$(c)$ Alien species invasion
$(d)$ Co-extinction