Final answer:
A digestive system is considered more advanced because it involves a one-way digestive tract, allowing for efficient digestion and absorption of nutrients. This type of system also allows for specialization of different regions along the tract. In contrast, an incomplete digestive system lacks a mouth and anus, relying on extracellular digestion, which is less efficient and limited.
Step-by-step explanation:
A digestive system is considered more advanced because it involves a one-way digestive tract, which allows for a more efficient and specialized breakdown of food. In this type of digestive system, food moves through the digestive tract in a single direction, starting from the mouth and ending at the anus. This one-way flow ensures that food is thoroughly digested and nutrients are efficiently absorbed.
Additionally, having a one-way digestive tract allows for the specialization of different regions along the tract. For example, in monogastric digestive systems like humans, the stomach is highly acidic to break down proteins, while the small intestine is responsible for the absorption of nutrients.
On the other hand, an incomplete digestive system, which lacks a mouth and anus, is less advanced because it relies on extracellular digestion. In this process, digestion occurs outside the cells in the digestive cavity, making it less efficient and limiting the types of food that can be digested.