Which of the following organisms does not have an endoskeleton of bones?

Options

A. Frog and lizard
B. Snail and cockroach
C. Fish and snake
D. All of these

Explanation

To determine which of the following organisms does not have an endoskeleton of bones, we will analyze each option provided.

1. **Identify the organisms**: The organisms mentioned are a frog, a lizard, a snail, a cockroach, a fish, and a snake.

2. **Classify the organisms**:
- **Frog and Lizard**: Both of these organisms belong to the phylum Chordata, which means they have an endoskeleton made of bones.
- **Snail**: Snails do not have an endoskeleton made of bones. They have a muscular body and possess an exoskeleton made of calcium carbonate.
- **Cockroach**: Cockroaches also do not have an endoskeleton made of bones. They have an exoskeleton made of chitin, which is found outside their body.
- **Fish and Snake**: Both fish and snakes have an endoskeleton made of bones, as they are also part of the phylum Chordata.

3. **Conclusion**: The organisms that do not have an endoskeleton of bones are the snail and the cockroach. Therefore, the correct answer is either the snail or the cockroach.

4. **Final Answer**: Snail and Cockroach do not have an endoskeleton of bones.