The correct option is D. Its body absorbs digested food. Detailed Explanation:

1. Understanding Tapeworms:
2. Tapeworms are parasitic flatworms belonging to the class Cestoda. They are typically found in the intestines of their hosts, which can be various animals, including humans.
3. Lack of Alimentary Canal:
4. An alimentary canal is a continuous tube that runs from the mouth to the anus, allowing for the ingestion, digestion, and excretion of food. Tapeworms do not have this structure. Instead, they have a flat, segmented body that is adapted to their parasitic lifestyle.
5. Absorption of Nutrients:
6. Tapeworms do not ingest food in the traditional sense. Instead, they absorb nutrients directly through their skin (tegument) from the host's digested food. The host's digestive enzymes break down the food into simpler molecules, which are then absorbed by the tapeworm. This is why option D is correct: the tapeworm's body is specialized for absorbing already digested food.
7. Why Other Options Are Incorrect:
8. A. It is autotrophic: This option is incorrect because autotrophic organisms can produce their own food through processes like photosynthesis or chemosynthesis. Tapeworms are heterotrophic, meaning they rely on other organisms (their hosts) for nutrients. They do not have the ability to synthesize their own food.
9. B. It does not feed: This statement is misleading. While it is true that tapeworms do not feed in the conventional sense (i.e., they do not consume food through a mouth), they still obtain nutrients by absorbing them from the host's digested food. Therefore, saying they do not feed at all is inaccurate.
10. C. It has no enzymes: While it is true that tapeworms do not produce digestive enzymes like many other organisms, this does not explain the absence of an alimentary canal. The lack of enzymes is a result of their parasitic lifestyle, as they rely on the host's digestive processes. Thus, this option does not address the question of why they lack an alimentary canal.

Summary of Key Points:

• Tapeworms absorb nutrients directly through their skin from the host's digested food.
• They are heterotrophic and do not produce their own food.
• The absence of an alimentary canal is an adaptation to their parasitic lifestyle.
• Other options (A, B, C) do not accurately describe the feeding mechanism or lifestyle of tapeworms.

This understanding of tapeworms and their unique adaptations is crucial for grasping the broader concepts of parasitism and nutrient absorption in biology.