Which of the following muscular disorders is inherited?

Which sentence is true for the disease Tetany?

At times,the ligaments are overstretched or torn. This condition is called:

In old age, people often suffer from stiff and inflamed joints. What is this condition called? What are the possible reasons for these symptoms?

Gout happens due to the accumulation of $...$ in joints.

Which of the following is an incorrect statement about myasthenia gravis?
$(I)$ It is not an autoimmune disorder.
$(II)$ It affects the neuromuscular junction.
$(III)$ It occurs due to low $Ca^{++}$ in body fluid.
$(IV)$ Paralysis of skeletal muscle is a symptom of myasthenia gravis.