How many of the following organisms are considered as Ecto - parasites - Lice, Ticks, Copepods, Cuscuta, Taenia, Ascaris, Liver fluke

Answer

To determine how many of the listed organisms are considered ectoparasites, we will analyze each organism based on the definition of ectoparasites.

### Step-by-Step Solution

1. **Understand the Definition of Ectoparasites**:
- Ectoparasites are organisms that live on the outer surface of a host and derive nutrients from it. They typically attach to the host's skin or outer layers.

2. **List the Organisms**:
- The organisms provided in the question are:
- Lice
- Ticks
- Copepods
- Cuscuta
- Taenia
- Ascaris
- Liver fluke

3. **Identify Ectoparasites**:
- **Lice**: These are ectoparasites as they live on the hair and skin of their hosts.
- **Ticks**: Ticks are also ectoparasites; they attach to the skin of their hosts to feed on blood.
- **Copepods**: Some copepods can be ectoparasitic, particularly those that attach to fish.
- **Cuscuta**: This is a plant that is a parasitic vine, but it does not fit the definition of an ectoparasite as it is not an animal.
- **Taenia**: This is a genus of tapeworms, which are endoparasites living inside the host's intestines.
- **Ascaris**: This is a genus of roundworms that are also endoparasites, living in the intestines of their hosts.
- **Liver fluke**: This is another example of an endoparasite, as it lives inside the liver of its host.

4. **Count the Ectoparasites**:
- From the analysis:
- Ectoparasites identified: Lice, Ticks, Copepods (Cuscuta is not included).
- Total number of ectoparasites: 3 (Lice, Ticks, Copepods).

### Final Answer:
**There are 3 ectoparasites among the listed organisms: Lice, Ticks, and Copepods.**

---