Practice Pakistan questions with answers and explanations.
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.
Many fishes swim through lateral waves produced by axial muscles acting on the vertebral column. This converts muscular contractions into forward movement.
Choose an option to check your answer.
The rib cage protects the heart and lungs. Damage can threaten breathing and circulation because these organs lie within the thoracic cavity.
Choose an option to check your answer.
Chitin is a tough polysaccharide found in arthropod exoskeletons and fungal walls. Bone is living connective tissue mineralized with calcium salts.
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.
A rigid external skeleton restricts growth. Arthropods solve this by molting the old cuticle and expanding before the new one hardens.
Choose an option to check your answer.
Ciliary beating can move the whole organism or generate water currents for feeding and respiration. In small aquatic forms, this is an efficient non-muscular mechanism.
Choose an option to check your answer.
Comparative anatomy links structure with function. Skeletons differ because animals face different demands such as swimming, jumping, flying, burrowing, or protection.
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.
Tendons contain dense collagen fibers. This structure resists tension and transfers force from muscles to bones or other hard parts.
Choose an option to check your answer.
Large terrestrial animals need strong support systems to resist gravity, maintain posture, and permit locomotion. Skeletons distribute mechanical loads across the body.
Choose an option to check your answer.
The axon carries nerve impulses away from the neuron cell body. Dendrites mainly receive signals, while synapses allow communication with other cells.
