That jelly-like blob sometimes floating in homemade vinegar isn't mold. It's a film of cellulose produced by acetic acid bacteria, which turn the alcohol in wine or cider into acetic acid as they consume oxygen. In the early 1860s, Louis Pasteur showed that vinegar-making is the work of these living microbes, not a purely chemical oxidation.
Chlorine on its own is fairly gentle. But when it combines with urine, sweat and other grime from swimmers, it forms chloramines, which cause stinging eyes and that classic 'chlorine smell'. A well-kept pool barely smells at all. Shower before you swim and never pee in the water.
Muscle mass slowly shrinks with age, putting independence at risk. But in 1990, a study had nursing home residents aged 86 to 96 train their legs for eight weeks: their strength more than doubled. Muscle responds to training at any age. Getting up from a chair without using your hands is already an exercise.