In Myasthenia gravis . . . . . . is affected.

Assertion: Inflammation of a skeletal joint may immobilize the movements of the joint.
Reason: Uric acid crystals in the joint cavity and ossification of articular cartilage lead to this.

Muscular dystrophy in humans is a

In case of severe tetany in muscle,the animal dies due to:

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$:
Osteoporosis is characterised by decreased bone mass and increased chances of fractures.
Reason $(R)$:
Common cause of osteoporosis is increased levels of estrogen.
In the light of the above statements,choose the most appropriate answer from the options given below:

Sprain is caused due to excessive pulling of