Short answers, pulled from the story.
Swimming is the self-propulsion of a person through water for recreation, sport, exercise, or survival. The human body floats because it has an average relative density of 0.98 compared to water, though buoyancy varies with body fat, lung inflation, muscle content, centre of gravity, and water salinity.
The four main strokes used in competition and recreational swimming are the front crawl, breaststroke, backstroke, and butterfly. The front crawl, also known as freestyle, is widely regarded as the fastest of the four.
Swimming was introduced as a competitive sporting event at the 1896 Summer Olympics in Athens, Greece. The current Olympic program includes events from 50 m to 1500 m across all four main strokes and the medley.
The butterfly was developed in the 1930s and was considered a variant of the breaststroke until it was accepted as a separate style in 1953.
Drowning is one of the primary risks of swimming. From 2005 to 2014, an average of 3,536 fatal unintentional drownings occurred each year in the United States, approximating 10 deaths a day and 67 deaths a week.
Swimming is governed internationally by World Aquatics, formerly known as FINA, the Fédération Internationale de Natation, until it adopted its current name in December 2022. World Aquatics recognizes 25 meter and 50 meter pools for international competition.
Human babies demonstrate an innate swimming or diving reflex from newborn until approximately ten months of age. When immersed, they spontaneously hold their breath, slow their heart rate, and reduce blood circulation to the fingers and toes, a response involving apnea, reflex bradycardia, and peripheral vasoconstriction.