How does amyotrophic lateral sclerosis (ALS) typically affect the body?

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that primarily affects motor neurons in the brain and spinal cord. As motor neurons degenerate and die, the brain can no longer initiate and control muscle movement, leading to a range of motor symptoms.

The correct choice reflects the hallmark symptoms of ALS, which include muscle weakness and atrophy. As the disease progresses, individuals experience a gradual loss of muscle function, resulting in weakness that affects the limbs, swallowing, and breathing. Atrophy occurs because the muscles are not receiving the necessary nerve impulses to function, leading to decreased muscle mass. This weakening of muscles can significantly impact daily activities and quality of life.

The other options do not accurately represent the effects of ALS. Increased sensory perception is not a characteristic of ALS; instead, the focus is on the decline in motor functions. There is also no improvement in motor coordination; rather, coordination may become impaired as the muscles weaken. Furthermore, ALS does not cure neurodegenerative conditions; it is itself a neurodegenerative disorder. These characteristics highlight the specific and detrimental impact of ALS on the nervous system and muscle function.