Final answer:
Myasthenia gravis is exacerbated by stress, infection, and cold weather, as all of these factors can stress the body and potentially lead to increased production of autoantibodies against acetylcholine receptors. These receptors are crucial for the transmission of signals that enable muscle contraction.
Step-by-step explanation:
Factors that can precipitate myasthenia gravis (MG) include stress, infection, and cold weather, so the correct answer is d) All of the above. Myasthenia gravis is an autoimmune disease where the body produces autoantibodies directed against acetylcholine receptors at the neuromuscular junction. These antibodies disrupt signal transmission between nerves and muscles, leading to muscle weakness and fatigue.
Stress can exacerbate MG symptoms by altering the immune system's functioning, potentially increasing the production of autoantibodies. Infections can act as a stressor on the body and may trigger or worsen the symptoms of MG. Cold weather may also exacerbate symptoms, as it can lead to increased muscle stiffness and difficulty in muscle movement.