The great white shark is very well known for its size, with the  largest individuals known to have approached or exceeded 6 metres  (20 ft) in length and 2,268 kilograms (5,000 lb) in weight. It  reaches maturity at around 15 years of age and can have a life span  of over 30 years.
Benign fasciculation syndrome is characterized by occasional or nearly continuous twitching of various skeletal (voluntary) muscles in the body. This type of muscle twitching can also be seen in association with serious disorders like spinal injury, multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS).
Signs and Symptoms. ALS affects the upper motor neurons, which are in the brain, and the lower motor neurons, which are in the spinal cord and brainstem. Upper motor neuron degeneration generally causesspasticity (tightness in a muscle), while lower motor neuron degeneration causes muscle weakness, muscle atrophy(shrinkage of muscles) and twitching. These can occur in combination in ALS, as upper and lower motor neurons are being lost at the same time.