Chapter 32, Problem 1SQ

Summary Introduction

Introduction:

A skeletal system comprises bones, ligament, and cartilage that help an individual in movement and locomotion. Muscles are attached to the skeletal system, which helps in generating the movement. Skeletal system also protects the soft organs of the body.

Answer to Problem 1SQ

Correct answer:

A hydrostatic skeletal system consist of a fluid-filled chamber or chambers. Hence, the correct answer is option a.

Explanation of Solution

Reason for correct answer:

Option a. is given as “chamber or chambers.”

Hydrostatic skeletal system is present in soft-bodied invertebrates such as worms and sea anemones. A hydrostatic skeletal is made up of fluid-filled internal chambers. For example, the coelom of an earthworm is divided into many fluid-filled chambers. These chambers help in movement of invertebrates.

Reason for incorrect answer:

Option b. is given as, “hardened plates at the surface of a body.”

An exoskeleton is made up of hard plates at the external part of the body. The exoskeleton is present in arthropods. The hard external shell receives the force of muscle contraction and protects the soft body tissue of the arthropods. Hence, option b. is incorrect.

Option c. is given as, “internal hard plates.”

An endoskeleton consists of internal hard plates. Endoskeleton is present in echinoderms. For example, the endoskeleton of sea stars consists of hardened calcium-rich plates. Hence, option b. is incorrect.

Option d. is given as, “none of the above.”

A hydrostatic skeletal is made up of fluid-filled internal chambers. Hence, option d. is incorrect.

Hence, the options b., c., and d. are incorrect.

Conclusion

A hydrostatic chamber is made up of a fluid-filled chamber. Hydrostatic skeletal is present in earthworms. Thus, the correct option is a.