annotate the following passage

"Yes, it's fifteen," Ed Regis said, nodding.
"You don't know for sure?" Malcolm said, affecting astonishment.
Wu smiled. "I stopped counting," he said, "after the first dozen. And you have to realize that sometimes we
think we
have an animal correctly
made-from the standpoint of the DNA, which is our basic work-and the animal grows
for six months and then something
untoward happens. And we realize there is some error. A releaser gene isn't
operating. A
hormone not being released. Or some other problem in the developmental sequence. So we have to go
back to the drawing board with that animal, so to speak." He smiled. "At one time, I thought I had more than twenty
species. But now, only fifteen."
"And is one of the fifteen species a-" Malcolm turned to Grant. "What was the name?"
"Procompsognathus," Grant said.
"You have made some procompsognathuses, or whatever they're called?" Malcolm asked.
"Oh yes," Wu said immediately. "Compys are very distinctive animals. And, we made an unusually large number
of them."
"Why is that?"
"Well, we want Jurassic Park to be as real an environment as possible-as authentic as possible-and the
procompsognathids are actual scavengers from the Jurassic period. Rather like jackals. So we wanted to have the
compys around to clean up."
"You mean to dispose of carcasses?"
"Yes, if there were any. But with only two hundred and thirty-odd animals in our total population, we don't have
many carcasses," Wu said. "That wasn't the primary objective. Actually, we wanted the compys for another kind of
waste management entirely."
"Which was?"
"Well," Wu said, "we have some very big herbivores on this island. We have specifically tried not to breed the
biggest sauropods, but even so, we've got several animals in excess of thirty tons walking around out there, and many
others in the five- to ten-ton area. That gives us two problems. One is feeding them, and in fact we must import food to
the island every two weeks. There is no way an island this small can support these animals for any time.
"But the other problem is waste. I don't know if you've ever seen elephant droppings," Wu said, "but they are
substantial. Each spoor is roughly the size of a soccer ball. Imagine the droppings of a brontosaur, ten times as large.
Now imagine the droppings of a herd of such animals, as we keep here. And the largest animals do not digest their food
terribly well, so that they excrete a great deal. And in the sixty million years since dinosaurs disappeared, apparently the
bacteria that specialize in breaking down their feces disappeared, too. At least, the sauropod feces don't decompose
readily."
"That's a problem," Malcolm said.
"I assure you it is," Wu said, not smiling. "We had a hell of a time trying to solve it. You probably know that in
Africa there is a specific insect, the dung beetle, which eats elephant feces. Many other large species have associated
creatures that have evolved to eat their excrement. Well, it turns out that compys will eat the feces of large herbivor
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