The basic unit of all living things is:

A patient with suspected meningitis involuntarily flexes her knees when her head is flexed toward her chest. This is called:

A) Kernig sign. B) Grey Turner sign. C) Cullen sign. D) Brudzinski sign.

Which of the following organs or body systems requires a constant blood supply, regardless of external factors?

A) Skin B) Muscles C) Kidneys D) Gastrointestinal tract