Biodiversity loss occurs due to
(i) habitat loss and fragmentation
(ii) co-extinction
(iii) over-exploitation
(iv) alien species invasion.
(a) (i) and (ii)
(b) (i), (ii) and (iii)
(c) (ii), (iii) and (iv)
(d) (i), (ii), (iii) and (iv)

Options

A. (i) and (ii)
B. (i), (ii) and (iii)
C. (ii), (iii) and (iv)
D. (i), (ii), (iii) and (iv)

Answer

To determine the correct answer to the question about the causes of biodiversity loss, we need to analyze each of the given options and the reasons behind biodiversity loss.

### Step-by-Step Solution:

1. **Understanding Biodiversity Loss**:
Biodiversity loss refers to the decline in the variety of life in a particular habitat or ecosystem. It can lead to species extinction and is influenced by several factors.

2. **Identifying the Causes**:
The question lists four potential causes of biodiversity loss:
- (i) Habitat loss and fragmentation
- (ii) Co-extinction
- (iii) Over-exploitation
- (iv) Alien species invasion

3. **Analyzing Each Cause**:
- **Habitat Loss and Fragmentation**: This occurs when natural habitats are destroyed or divided into smaller patches, leading to a decrease in species that rely on those habitats.
- **Co-extinction**: This refers to the phenomenon where the extinction of one species leads to the extinction of another species that depends on it.
- **Over-exploitation**: This involves the excessive harvesting of species, which can reduce their populations to critical levels, making them vulnerable to extinction.
- **Alien Species Invasion**: When non-native species are introduced to an ecosystem, they can outcompete native species for resources, leading to declines or extinctions of those native species.

4. **Conclusion**:
All four factors listed (i, ii, iii, iv) contribute to biodiversity loss. Therefore, the correct answer is:
**(d) (i), (ii), (iii) and (iv)**.

### Final Answer:
(d) (i), (ii), (iii) and (iv)

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