The longest bone in the human body is the femur, which is located in the thigh. The femur, or thigh bone, extends from the hip to the knee and is the largest and strongest bone in the human skeleton.

A pacemaker is a medical device used to regulate the heartbeat in individuals with abnormal heart rhythms (arrhythmias). It is often implanted in the chest to help control the heart's rhythm and treat conditions like bradycardia (slow heart rate) or other rhythm disorders. Pacemakers are typically prescribed by cardiologists, specialized doctors who diagnose and treat heart-related conditions. The decision to implant a pacemaker is made by a healthcare provider based on the patient's specific medical condition and needs.

1 volt = 1 joule / 1 coulomb

This equation represents the definition of voltage (in volts). It states that one volt is equal to one joule of energy per one coulomb of charge. Voltage measures the electric potential difference between two points and is a fundamental concept in electrical physics.

The plants that never produce flowers are called "cryptogams." Cryptogams include plants such as ferns, mosses, liverworts, and algae. Unlike flowering plants (angiosperms), which reproduce through seeds enclosed within flowers, cryptogams reproduce through spores and do not produce true flowers. Cryptogams are considered more primitive in evolutionary terms compared to angiosperms, which are the most dominant group of plants on Earth today.

Actually, the locomotor part of a hydra is not its tentacles. Hydras move by a remarkable way called "looping." They attach one end of their body to a surface and then release the other end, allowing it to move and attach again. This looping movement is facilitated by the contraction and expansion of the body, rather than the use of tentacles. Tentacles are specialized structures primarily used for feeding and defense in hydras.