Parathormone of parathyroid gland increases the blood calcium level. Removal of parathyroid gland decreases the blood calcium level due to its increased excretion in urine. It causes increased excitability of muscles and their sustained contraction referred to as parathyroid tetany. Myxedema is caused by hypothyroidism in adults while Addison’s disease is caused by the presence of ineffective ACTH. Simmond's disease is caused by the destruction of the anterior pituitary lobe. Thus, the correct answer is A.

A sprain is an injury to the ligaments around a joint. Ligaments are strong, flexible fibers that hold bones together. When a ligament is stretched too far or tears, the joint will become painful and stress.
Tonus is the slight, continuous contraction of a muscle.
Tetany consists of the involuntary contraction of muscles.
Fatigue is the general overall feeling of tiredness and lack of energy.
So, the correct answer is option C.

Arthritis is a disorder of the joints. It involves inflammation of one or more joints. When affected by arthritis, the joint or joints affected may be painful to move, may move in unusual directions or may be immobile completely. Osteoporosis is a disease of bone where there is reduced bone mineral density, increasing the likelihood of fractures. 

• Skeletal system consists of a framework of bones and a few cartilages.
  
• Osteoporosis is defined as a low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk.
• It occurs due to various fractures such as calcium deficiency, hyperparathyroidism, estrogen deficiency in females etc,
• Hence osteoporosis →→ Decrease in bone mass and higher chances of fractures with advancing age.
• So, the correct answer is 'Osteoporosis →→ Decrease in bone mass and higher chances of fractures with advancing age'.

Lathyrus sativus also known as Kesari dal is mainly consumed by poor people. It causes paralysis because of the action of neurotoxin OAA present in it.

Dislocation is a disease which occurs when there is an abnormal separation in the joint, where two or more bones meet. Most common sites of dislocation are shoulder, hip, patella, ankle and fingers. Dislocations are often caused by sudden trauma on the joint like an impact or fall. Mechanical agents are the major cause of dislocation, sprains, injuries, fractures etc.

The correct combination of disease due to hyposecretion of these hormones:-

Tetany is related with parathyroid hormone or parathormone, it is responsible for calcium metabolism, the hyposecretion of parathormone lowers the blood calcium that results in the increasing the excitability of nerves and muscles.

The deficiency of calcium and vitamin D are the major causative factor of osteoporosis .

Muscular dystrophy is a genetic disease, osteoporosis is the decrease in bone mass, which leads to higher chances of fractures with advancing age.

Osteoporosis causes bones to become weak and brittle — so brittle that a fall or even mild stresses such as bending over or coughing can cause a fracture. Osteoporosis-related fractures most commonly occur in the hip, wrist or spine. So the correct option is 'decreased level of progesterone'.

Paraplegia is an impairment in motor or sensory function of the lower extremities. It is usually the result of spinal cord injury.

Osteoporosis is a progressive bone disease characterized by a decrease in bone mass and density which can lead to an increased risk of fracture. In osteoporosis, the bone mineral density is reduced. Low levels of vitamin D is associated with osteoporosis.
Therefore, the correct answer is option A.

Myasthenia gravis is an autoimmune disease that destroys the skeletal muscles responsible for actions such as swallowing, breathing, etc. It is caused due to the inability of muscles to respond to the nerve impulse due to the destruction of the receptors of acetylcholine on them. The acetylcholine is secreted from the neurons at the neuromuscular junction which is not perceived by the muscles as their receptors have been destroyed by the antibodies.

Osteoporosis is an age related disorder of skeletal system caused due to weakening of bones by decreased Ca++ and oestrogen levels. Osetrogen helps in decreasing the resorption of bone by decreasing osteoclastic activity. As the oestrogen levels decrease the osteoclastic activity increases and more ca++ is withdrawn into blood from bone resulting in osteoporosis. 

Osteoporosis is bone disorder in which the Ca++ is decreased resulting in decreased bone mass. This may lead to fractures.

Lathyrus sativus (grass pea) causes the neurological disorder known as lathyrism or neurolathyrism. It has high concentration of neurotoxin β-oxalyl-L-α,β-diaminopropionic acid which causes paralysis. It is a poison of mitochondria which causes cell death.

An autoimmune disorder is a condition where body's own immune system attacks and destroys own tissues by mistake. Myasthenia gravis is an autoimmune disorder in which body produces antibodies agaist the neurotransmitter acetylcholine nicotinic in skeletal muscles. It is characterized by the muscle weakness. 

Tetany is rapid spasms in muscles due to low calcium ions in the body fluid or blood. Hyposecretion of parathormone lowers concentration of calcium ions in the blood due to excretion of calcium in urine, this increases the excitability of nerves and muscles, causing cramp and convulsions, this disorder is known as tetany. 

• A decline in a muscle's ability to maintain a constant level of force, or tension after prolonged, repetitive stimulation is called tetanus.
  
• A tetanic contraction is a sustainable contraction evoked when motor nerve innervates a skeletal muscle emitting action potential at a very high rate.

A. Muscle dystrophy: It involves progressive degeneration of skeletal muscle due to a genetic defect.

• Muscular dystrophy is a collection of muscle-wasting conditions. 
  
• A lack of a protein called dystrophin is the main cause of muscular dystrophy.

A sprain is a stretching or tearing of ligaments which are the tough bands of fibrous tissue that connect two bones together in the joints. The most common causes of sprains are falling, twisting etc. These types of injuries may cause the joint to move out of its normal range of movement that causes the tearing or stretching of the ligament. So, the correct answer is 'Overstretching of ligament'.

A sprain is a stretching or tearing of ligaments which are the tough bands of fibrous tissue that connect two bones together in the joints. A sprain results in an overstretch or tear of the ligaments supporting that joint. 

The ligament is the connective tissue which attaches two or more bones together to form a joint. When the ligament breaks, the two bones cannot be held together and dislocate. Generally, when the person met with an accident and the ligament is broken, there are chances that the person will suffer from the dislocation of the bones. 

• Osteoporosis is defined as low bone mass and microarchitectural deterioration of the bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk.
• It may occur due to various reasons such as calcium deficiency, increase in osteoclastic or osteoblastic activity, age, estrogen deficiency in females etc.
• Hence bones become fragile (easily broken or damaged) due to osteoporosis.
• So,the correct answer is 'Osteoporosis'.

Myasthenia gravis is a disease caused due to the antibodies produced by an immune system that blocks or destroy the receptor sites for a neurotransmitter called acetylcholine. The enzyme esterase or acetylcholine esterase break the acetylcholine and deactivates the neurotransmitter to stop muscle activation. 

Symptoms of tetanus include
 a)Tetanus often begins with mild spasms in the jaw muscles known as lockjaw. The spasms can also affect the facial muscles and experience spasms and stiffness in various muscles, especially those in jaw, abdomen, chest, back, and neck.
b)Muscle cramps or spasms in your legs, fever, high blood pressure etc
Hypoparathyroidism is decreased function of the parathyroid glands with underproduction of parathyroid hormone. This can lead to low levels of calcium in the blood, often causing cramping and twitching of muscles or tetany (involuntary muscle contraction).
Hence parathyroid gland is associated with tetanus.
So, the correct answer is 'Parathyroid gland'.

• Autoimmune diseases are a group of disorders in which tissue injury is caused by humoral(autoantibodies)or cell-mediated(by autoreactive T cells) immune response to self-antigens.
  
• Myasthenia gravis is caused by an autoantibody against muscle antigen and acetylcholine receptor antigen.
  
• Myasthenia gravis is characterized by increased muscular weakness the make one fatigue. speaking, breathing and talking becomes tired some. Hence myasthenia gravis is an example of autoimmune disease.
  
• So, the correct answer is 'Autoimmune disease'.
  

• Muscular dystrophy is a group of inherited muscle diseases in which muscle fibers are unusually susceptible to damage.
  
• It is characterized by progressive skeletal muscle degeneration, defects in muscle proteins and the death of muscle cell and tissue.
• Hence progressive degeneration of skeletal muscle, mostly due to genetic disorder occurs in muscular dystrophy.
• So, the correct answer is 'Muscular dystrophy'.