I am no expert on the subject, but it seems that someone should start this entry. Some primary reasons that animals become extinct include loss of habitat, changing climatic conditions, introduction of non-native species or predators into their habitat, pollutants, and predation by humans.
yes
they are getting killed by other animals thye are food to some other animals
Which of these is not a reason that species become extinct
It has to do with the food chain. Say if T-Rex are extinct, the animals it eats over-populate and take all the food or water. Slowly, all the animals start to become extinct. Or, if a certain animal becomes extinct, the things it eats over-populate and the things that eat it normally become extinct.
It is many reasons. But the most common reason is humans, who "hunts" animals. Many races in South-America and Africa have been extinct, because humans are burning down the forrest. Many animals are endangered, because humans are greedy.
pollution is contaminating the animals and their food.
Creating Cities, chopping forest and other related causes.
Sharks' food supplies have not gone away.
They aren't extinct and if you mean why did they become endangered it's because they got hunted, but now they are a protected bird.
Koalas are not extinct.
Many people fart for no reason at all yet continue to read this message.
they are believed to have become extinct around 65 million years ago...... the reason they became extinct is that a huge meteor hit the earth and wiped the whole dinosaur-related population out .... just aswell this happened otherwise it is unlikely we would exist now....