Parathormone released by the parathyroid gland elevates the level of Ca²⁺ in blood. The deficiency of this hormone lowers blood Ca²⁺. As a result, the excitability of muscles and nerves increases causing tetany -sustained contraction.

Correct Option: A

Parathormone released by the parathyroid gland elevates the level of Ca²⁺ in blood. The deficiency of this hormone lowers blood Ca²⁺. As a result, the excitability of muscles and nerves increases causing tetany -sustained contraction.

Floating ribs are 2- pairs (11th and 12th pair) which are not attached to sternum.

Correct Option: D

Floating ribs are 2- pairs (11th and 12th pair) which are not attached to sternum.

Hinge joint: elbow joint, knee joint, ankle joint, inter phalangeal joint. Gliding joint: Intercarpal joint, intertarsal joint, sternoclavicular joint and joint between pre and post zygapophysis of adjacent vertebra.
Fibrous joint (Synarthroses): Joints of cranium - bones. Joints between teeth and Jaw bones.
Cartilaginous joint (Amphiarthroses): Joints between mammalian vertebrae and two innominate bones (pubic symphysis).

Correct Option: B

Hinge joint: elbow joint, knee joint, ankle joint, inter phalangeal joint. Gliding joint: Intercarpal joint, intertarsal joint, sternoclavicular joint and joint between pre and post zygapophysis of adjacent vertebra.
Fibrous joint (Synarthroses): Joints of cranium - bones. Joints between teeth and Jaw bones.
Cartilaginous joint (Amphiarthroses): Joints between mammalian vertebrae and two innominate bones (pubic symphysis).

Each half of pectoral girdle has two bones i.e. clavicle and scapula. A spine like, acromian process is attached to scapula for articulation with clavicle bone.

Correct Option: B

Each half of pectoral girdle has two bones i.e. clavicle and scapula. A spine like, acromian process is attached to scapula for articulation with clavicle bone.

ATPase enzyme is located in the myosin cross bridge heads. Actin forms the light or I- Band. Actin slides over myosin during contraction. Troponin protein is involved in establishing connection with myosin cross bridges. Actin is not involved in muscle contraction. It is also an ATPase (an enzyme) which is activated by Ca²⁺ and Mg²⁺ ions. Hence, ATPase enzyme is located in myosin.

Correct Option: C

ATPase enzyme is located in the myosin cross bridge heads. Actin forms the light or I- Band. Actin slides over myosin during contraction. Troponin protein is involved in establishing connection with myosin cross bridges. Actin is not involved in muscle contraction. It is also an ATPase (an enzyme) which is activated by Ca²⁺ and Mg²⁺ ions. Hence, ATPase enzyme is located in myosin.