Which one of the following is categorised as a parasite in true sense

Options

A. The female Anopheles bites and sucks blood from humans.
B. Human foetus developing inside the uterus draws nourishment form the mother
C. Head louse living on the human scalp as well as laying eggs on human hair
D. The cuckoo (koel) lay its eggs in crow's nest

Explanation

**Step-by-Step Solution:**

1. **Understanding Parasites**: A parasite is defined as an organism that lives on or in a host organism and gets its food at the expense of its host. True parasites are those that cannot complete their life cycle without a host.

2. **Analyzing the Options**:
- **Option A**: Female Anopheles mosquito bites and sucks blood from humans.
- **Analysis**: While it does require blood for reproduction, it can complete its life cycle without a human host. Therefore, it is not a true parasite.

- **Option B**: Human fetus developing inside the uterus draws nourishment from the mother.
- **Analysis**: This is a case of maternal care, not parasitism. The fetus is dependent on the mother, but it is part of the same organism's life cycle. Hence, this is not a true parasite.

- **Option C**: Head lice living on the human scalp and laying eggs on human hair.
- **Analysis**: Head lice live, feed, and reproduce on the human host. They are entirely dependent on humans for their life cycle, making them a true parasite.

- **Option D**: Cuckoo bird laying eggs in a crow's nest.
- **Analysis**: The cuckoo bird is known as a brood parasite; it relies on other birds to raise its young. However, it does not depend on the host for its entire life cycle, so it is not classified as a true parasite.

3. **Conclusion**: Based on the analyses, the organism that fits the definition of a true parasite is **head lice (Option C)**, as they are completely dependent on humans for their survival and reproduction.

**Final Answer**: Head lice living on the human scalp as well as laying eggs on human hair.

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