When water freezes it forms a lattice pattern and expands. Because the water forms a crystal lattice when frozen, it's volume increases because the water molecules take up a lot of space but they aren't very compact.
The right answer is screening test.
In medicine, screening consists of looking for one or more diseases or abnormalities known as "at risk" in individuals of a given population.
These investigations are followed or not by medical consultations, clinical examinations and treatments.
In addition, screening is a preliminary procedure (test or examination) to detect one or more characteristic signs or symptoms of a disease or syndrome and potentially leading to further investigation.