`-------- and --------` constitute our skeletal system.

Options

A. Bones and blood
B. Blood and lymph
C. Bones and cartilages
D. Bone and nervous

Answer

To answer the question "-------- and -------- constitute our skeletal system," we will identify the main components of the skeletal system step by step.

### Step-by-Step Solution:

1. **Understanding the Skeletal System**: The skeletal system serves as the central framework of our body. It provides structure, support, and protection for our organs.

2. **Identifying Components**: The primary components of the skeletal system include various structures. The most significant components are bones and connective tissues.

3. **Defining Bones**: Bones are rigid structures that make up the skeleton. They provide support, protect vital organs, and facilitate movement by serving as levers for muscles.

4. **Defining Cartilage**: Cartilage is a flexible connective tissue found in various parts of the body, including joints, the rib cage, and the ear. It provides cushioning and support, allowing for smooth movement at joints.

5. **Evaluating Options**:
- **Bones and Blood**: Incorrect, as blood is part of the circulatory system, not the skeletal system.
- **Blood and Lymph**: Incorrect, as both are fluids in the circulatory and lymphatic systems.
- **Bones and Cartilage**: Correct, as both are integral parts of the skeletal system.
- **Bones and Nerves**: Incorrect, as nerves are part of the nervous system.

6. **Conclusion**: The correct answer to the question is "bones and cartilage," as these two components constitute the skeletal system.

### Final Answer:
**Bones and Cartilage**