Blood transfer is limited by the type and Rh factor of the blood. Someone who has Rh-factor negative blood cannot receive blood with a positive type but a person with Rh-factor positive type blood can receive Rh-negative blood. Type O negative blood is the universal donor because it can be given to a person with any blood type. Type AB positive is the universal recipient meaning someone with this blood type can receive any other type of blood.

Heat is always transferred from warmer to cooler environments and conduction is the simplest way this transfer can occur. It is accomplished through direct contact between materials and materials like metals that transfer heat efficiently are called conductors while those that conduct heat poorly, such as plastic, are called insulators.

The nucleus of a eukaryotic cell contains the genetic material of the cell and is surrounded by cytoplasm which contains many organelles. These include:

Kinetic energy is the energy posessed by a moving object. Potential energy is stored energy in a stationary object based on its location, position, shape, or state.

The four planets closest to the Sun (Mercury, Venus, Earth, and Mars) are called terrestrial (Earth-like) planets because, like the Earth, they're solid with inner metal cores covered by rocky surfaces.