A partial parasite is
(a) Cuscuta
(b) Cassytha
(c) Arceuthobium
(d) Viscum

Options

A. Cuscuta
B. Cassytha
C. Arceuthobium
D. Viscum

Answer

To determine which of the given options is a partial parasite, we need to understand the characteristics of partial parasites.

### Step-by-Step Solution:

1. **Definition of Partial Parasite**: A partial parasite is a plant that relies on its host for certain nutrients, specifically water and minerals, but is capable of photosynthesis and can synthesize its own food due to the presence of chlorophyll.

2. **Analyze the Options**:
- **(a) Cuscuta**: This is a complete parasite that does not have chlorophyll and cannot perform photosynthesis. It relies entirely on its host for food, water, and minerals.
- **(b) Cassytha**: Similar to Cuscuta, Cassytha is also a complete parasite and does not have the ability to synthesize its own food.
- **(c) Arceuthobium**: This is another complete parasite that lacks chlorophyll and, therefore, cannot perform photosynthesis. It depends entirely on its host for all nutrients.
- **(d) Viscum**: Viscum, commonly known as mistletoe, is a partial parasite. It has chlorophyll and can perform photosynthesis, thus synthesizing its own food. It only relies on its host for water and minerals.

3. **Conclusion**: Based on the analysis, the correct answer is **(d) Viscum**, as it is the only option that fits the definition of a partial parasite.

### Final Answer:
**(d) Viscum**

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