First up in our comparisons are flatworms. Flatworms have an incomplete digestive tract, meaning that food can only enter and exit through one opening. Inside the flatworm phylum, we see two general types inside free living and many parasitic flatworms. It goes something like this. We see food being consumed through her mouth, moving there're a muscular pharynx and then from there into a very long and branching intestine. But since food could only enter and exit through one opening, the UN processed food has to move back out all the way through the system and then back out the mouth. And then, of course, we have tape worms. Tapeworms have essentially evolved to be one very long digestive system with their body. We have their head and at the tip, our Siris of either hooks or suckers. As for the body, we have a Siris of varied, long, repeatedly long repeated segments. Tapeworms are parasitic, living in their hosts intestine. Since they have picked their location pretty opportunity. Their food that they are able to access is already digested. Tapeworms are able to absorb this digested food straight through their body wall dodge being short for digested food as for why this is adaptive. Tapeworms have eliminated a lot of their bodily systems in favor of maximizing their reproduction. Inside. All of these body segments are both male and female reproductive organs that are using their undigested food to make a lot of eggs and pass them through the intestine and out of their hosts body. So tapeworms have eliminated ah lot of their body in favor of maximizing reproduction. It's not a tape. As for the general flatworm body, this could be adaptive as well. The intestines take up most of the body, and not only do they absorb the animals food, but they absorb other things as well, like oxygen. Since the digestive system does everything in animals, regular circulatory system might dio flatworms have evolved the need for no circulatory system at all, saving the energetic costs as well, so sometimes simple. While it may not be better in terms of the actual digestive system in favor of a complete one as well C, it can save the animal energy as well. Next up we have analysts, analysts have a complete digestive system or got our complete digestive tract again died short for digestive, meaning that food can enter one way and exit another for the General Angela digestive system, both free living and parasitic. We see food being consumed through a fair inks moving through the esophagus down to a crop where it could be stored. From there it goes through a gizzard where it could be processed from there into an intestine where nutrients could be absorbed. Yeah, and finally exiting out of the animals anise. Now, this sort of complex, more complex digestive system is adaptive because it allows for functional specialization. Yeah, this means that the body part can be divided in having each part serve its own task. We can directly see this inside analysts because their digestive system is complete. Food can enter one way and exit the other. We see it divided into multiple tasks. Ah, crop for storing food, a gizzard for processing it, and an intestine for actually absorbing. So we can see complexity could be adaptive as well as it allows for more specialized processing of food. Something things up. We have two very different types of animals. Flatworms have an incomplete digestive tract which isn't quite efficient as theano lead complete digestive tract, but it allows for a more simpler lifestyle, either having no need for circulatory system or most of its body systems at all. And we have analysts having a complete digestive tract allowing for functional specialization and better processing of their food.