Percentage of Endangered Species in Different Animal Groups:

Mammals:
- 25% of mammal species are at risk of extinction
- Examples of endangered mammals include tigers, gorillas, and elephants

Insects:
- Only a small percentage of insect species have been assessed for their conservation status
- However, some estimates suggest that 40% of insect species could be at risk of extinction in the coming decades
- Examples of endangered insects include monarch butterflies and honeybees

Amphibians:
- Approximately 41% of amphibian species are threatened with extinction
- This is the highest percentage of any major animal group
- Examples of endangered amphibians include frogs, salamanders, and toads

Reptiles:
- Approximately 20% of reptile species are threatened with extinction
- Examples of endangered reptiles include sea turtles and crocodiles

Explanation:
The correct answer to this question is option C, amphibians, as they have the highest percentage of endangered species. This is due to several factors, including habitat loss, pollution, climate change, and disease. Amphibians are also particularly vulnerable to these threats because they have permeable skin and rely on both aquatic and terrestrial ecosystems. Additionally, many amphibian species have small ranges and low population sizes, making them more susceptible to extinction. It is important to note, however, that all animal groups are facing threats to their survival, and conservation efforts are needed to protect biodiversity and prevent further extinctions.