Why is the development of a one - way digestive system important to the evolution of animals?

Evolution causes the change in the characteristic species of the population. This change helps the population to better adapt in their environment and can flourish their population.  

The digestive system of the organisms has also evolved from the simple to the complex for. The one way digestive system allows the efficient digestion of food and generation of more ATP. This type of digestive system has separate sections to perform each function efficiently.  

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.