Bees
Researcher George McGavin concluded that “We rely upon bees for just about every vegetable, flower and fruit around. They are a crucial terrestrial group and we would face mass starvation without them.” And let’s put it this way: no bees, no plants. Less plants, less animals and, more importantly, less oxygen! Of course, this is an extreme scenario, but our world would definitely be much more challenging without these tiny insects.