hand, face, crown (wristwatch), back
Grandfather clocks have "toe" molding around the base.
The clock stops when any part of your shoulders, chest or torso crosses the line. Head, arms and legs do not stop the clock.
Internal or biological clock
A clock has a neck and hands but no legs. The "neck" refers to the part of the clock that connects the face to the body, while the "hands" indicate the time. Despite these features, a clock does not have legs, making it a fitting answer to the riddle.
The biological clock that regulates the body's daily rhythms is called the circadian rhythm. It is controlled by a cluster of cells in the brain called the suprachiasmatic nucleus, which responds to light and dark signals to help synchronize our internal body clock with the external day-night cycle. This internal clock helps regulate functions such as sleep-wake cycles, hormone release, body temperature, and metabolism.
A person's body clock is the system of needs that your body takes. Your body will want to sleep during certain hours for example.
Internal or biological clock
The clock light is an integral part of the clock and is not replacable by itself
The pendulum is the part of a grandfather clock that swings back and forth. It regulates the timekeeping mechanism of the clock by controlling the rate at which the gears turn.
A part of a clock that starts with "pen" is the pendulum. The pendulum helps regulate the timekeeping of certain types of clocks by controlling the speed at which the clock's gears move.
A clock or a watch. They both have faces and hands, but no legs.
Pineal body (gland)
The body's temperature rises at night due to the natural circadian rhythm, which is the body's internal clock that regulates sleep-wake cycles. During the night, the body's metabolism slows down, leading to a slight increase in body temperature as a part of the body's natural processes.