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).
In brief: Yes. yes, and many twitches are NOT an indication of amyotrophic lateral sclerosis (ALS). Most twitches are the result of single nerve fibers stimulating contractions in a group of voluntary muscle cells..a so called motor unit..which can cause an area of muscle to twitch or wiggle. Larger twitches, 'starts' where a whole limb jerks, are something coming from the motor control in the brain.