Question

how can we say that human beings are threat to animals

Answer 1

we can say this because humans beings cut the forests therefore animals natural habitat is disturbed and their food chain is effected . we pollute the water bodies which kills the water animal. we pollute the air which is harmful for the animals to breathe .

Answer 2

we can say that human beings are threat to animals because
they kill animals for their own greed such as skill , skin, teeth etc
some people hunt animals for fun
hunters hunt animals for food
scientists kill them in order to make medicines