Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
Keratin is a tough structural protein in hair, nails, claws, and epidermis. It strengthens integumentary derivatives and improves protection.
Choose an option to check your answer.
Earthworms move when circular muscles lengthen segments and longitudinal muscles shorten them. The hydrostatic skeleton gives resistance for these shape changes.
Choose an option to check your answer.
Skeletons help support body weight and maintain posture. This is separate from digestion, excretion, or immune memory.
Choose an option to check your answer.
Tendons are tough connective tissues that attach muscles to bones. They transmit contractile force so bones move at joints.
Choose an option to check your answer.
Hydrostatic skeletons use fluid pressure inside body cavities to support soft tissues. Annelids are a standard example because their coelomic fluid works with muscles during movement.
Choose an option to check your answer.
Jointed appendages permit controlled walking and balance in arthropods. Losing a leg disrupts mechanical coordination even if other systems continue working.
Choose an option to check your answer.
Sharks and rays have skeletons largely made of cartilage. This gives flexible support and differs from the ossified skeleton of bony fishes.
Choose an option to check your answer.
Cartilage provides flexible support in joints, nose, ears, and early vertebrate skeletons. It resists compression while allowing shape and movement.
Choose an option to check your answer.
Fins help generate thrust, steering, and stability in water. They work with the muscular and skeletal systems to control aquatic movement.
Choose an option to check your answer.
Insects use thoracic muscles that move wings through the exoskeleton and wing articulation. Their flight mechanics depend on the arthropod body plan.
Choose an option to check your answer.
Bivalves close their shells using adductor muscles. These muscles pull the two valves together, protecting the soft body from predators and drying.
Choose an option to check your answer.
Skeletal muscle is striated and generally under voluntary control. It produces quick, powerful contractions needed for running, jumping, or escaping predators.
