Name the two types of skeletal system .

Explanation

**Step-by-Step Solution:**

1. **Understanding the Skeletal System**: The skeletal system is the framework of bones and cartilage that supports the body, protects vital organs, and allows for movement.

2. **Identifying the Types**: There are two main types of skeletal systems found in animals:
- **Internal Skeleton (Endoskeleton)**: This type of skeleton is located inside the body. It is made up of bones and cartilage, providing support and protection for internal organs. Examples include the skeletons of mammals, birds, and reptiles.
- **External Skeleton (Exoskeleton)**: This type of skeleton is found on the outside of the body. It provides protection and support, and is typically made of chitin or calcium carbonate. Examples include the skeletons of insects, crustaceans, and some mollusks.

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