A human's internal organs are protected mainly by the
a. Hydrostatic skeleton.
b. Axial skeleton.
c. Exoskeleton.
d. Appendicular skeleton.

Verified step by step guidance

1. Step 1: Understand the function of each type of skeleton mentioned in the options. For example, the hydrostatic skeleton is a fluid-filled structure found in soft-bodied organisms like worms, and the exoskeleton is an external protective covering found in arthropods like insects.
2. Step 2: Recall that humans are vertebrates and have an internal skeleton made of bones. This internal skeleton is divided into two main parts: the axial skeleton and the appendicular skeleton.
3. Step 3: Learn the components of the axial skeleton. It includes the skull, vertebral column, ribs, and sternum, which are responsible for protecting vital internal organs such as the brain, heart, and lungs.
4. Step 4: Compare the axial skeleton with the appendicular skeleton. The appendicular skeleton consists of the limbs and girdles, which are primarily involved in movement rather than protection of internal organs.
5. Step 5: Based on the information above, identify which skeleton is primarily responsible for protecting internal organs in humans.

Key Concepts

Axial Skeleton

The axial skeleton consists of the bones that form the long axis of the body, including the skull, vertebral column, and rib cage. It serves to protect vital organs such as the brain, heart, and lungs, providing a framework for the body and supporting the head and trunk.

Hydrostatic Skeleton

A hydrostatic skeleton is a structure found in some animals, such as jellyfish and earthworms, where fluid-filled cavities provide support and shape. This type of skeleton relies on the pressure of the fluid within the body to maintain form and facilitate movement, unlike the bony structures in humans.

Exoskeleton and Appendicular Skeleton

An exoskeleton is a rigid external covering found in some animals, like insects and crustaceans, providing protection and support. The appendicular skeleton includes the bones of the limbs and girdles, facilitating movement but not primarily protecting internal organs, which is the role of the axial skeleton.