Tapeworm has no alimentary canal, because

Options

A. It does not require nutrients
B. it feeds only when young
C. It absorbs nutrients through body surface
D. None of these

Answer

### Step-by-Step Solution:

1. **Understanding the Organism**: Tapeworms belong to the phylum Platyhelminthes and the class Cestoda. They are parasitic worms that live in the intestines of their hosts, often humans.

2. **Absence of Alimentary Canal**: Tapeworms do not have an alimentary canal, which is the digestive tract that includes a mouth and an anus. This absence is a characteristic feature of these organisms.

3. **Nutrient Absorption Method**: Instead of having a digestive system, tapeworms absorb nutrients directly through their skin. They utilize a process called diffusion to take in nutrients from the host's intestinal contents.

4. **Reason for No Mouth or Digestive System**: Since tapeworms absorb nutrients directly from their host, they do not need a true mouth or a digestive system. Their body is adapted to their parasitic lifestyle, allowing them to survive without these structures.

5. **Conclusion**: The reason tapeworms have no alimentary canal is that they absorb nutrients through their skin via diffusion, eliminating the need for a digestive system.