Complex sentence: Sweat is readily visualized by a topical indicator such as iodinated starch (minor test) or sodium alizarin sulphonate, both of which undergo a dramatic colour change when moistened by sweat.
Split into simpler sentences: Sweat is readily visualized by a topical indicator such as iodinated starch (minor test) or sodium alizarin sulphonate. Both of which undergo a dramatic colour change when moistened by sweat.