单项选择题

TEXT C
It is hard to love ants. Spiders and scorpions excepted, they are probably our least favorite insect. They give no honey; they do not brighten the air or chirp in hedgerows. Ants are small and dark and silent and live underground where they cannot be seen. They arc venomous and they bite. They teem and swarm, moving en masse, like robots, in cryptic legions. And they are ugly; their huge heads and tiny waists make their bodies seem like grotesque, anorexic versions of our own. The industry of ants is a constant reproach to us; their most surprising feature, their social organization, seems sinister and totalitarian. Only our luck in being several thousand times as big keeps us safe from them.
And ants, needless to say, do not love us. They hardly even notice us. This is hard to take. They challenge our anthropocentrism. For them, it seems we are not very important. And that is the truth of the matter. Ants arc the most successful organisms in evolutionary history: there are over 8,000 species, distributed everywhere on Earth except the polar regions. In Peru, 43 different kinds of ant have been recorded in a single tree. Compared with this, primates are just a flash in the pan. Ants antedate us and will undoubtedly outlast us. There are a million times more of them:10 million billion, it has been estimated, alive at any one time—a quarter of a million for every acre of land on the Earth’s surface.
The greatest number of ant species, and the most spectacular, are to be found in tropical rainforests and savannahs. It is a common but disconcerting experience in such places to witness an invasion of driver ants, a predatory tribe that hunts at night as well as in the day. Driver ants move in columns a foot or so in width and a hundred yards in length, each composed of millions of individual ants. Waking up in the darkness with a marauding column in your tent, it seems as though a thick black oiled rope is running over your bed, over you, across the wall and out again: an endless skein of insects, running along each other’s backs, antennae and mandibles threateningly erect. A column of driver ants will attack lizards, snakes, rodents, anything in its path. If you happen to be dead, the ants will eat you, too; if you are not, they will just bite you. With their preposterously over-developed jaws, individuals of the soldier castes that form the flank of the column can scissor human flesh with ease. These are the rottweilers of the myrmecological world.
Ants can eat us, but we cannot eat them with any pleasure. Unlike termites (which have a rich oily taste something like pork scratchings), ants, with a tough outer layer of chitin and a nasty whiff of formic acid in their body tissues, are generally indigestible, except by other ants. Even anteaters prefer termites. Ants, furthermore, are resistant to hard radiation and, in the case of some species, industrial pollution; some can live in deserts; some can float; some can slow their metabolism down and survive under water for days on end.
Apart from their great numbers, why does the writer call ants "the most successful organisms"