6A/M1 ( Grades: 6-8 ): Like other animals, human beings have body systems for obtaining and deriving energy from food and for defense, reproduction, and the coordination of body functions.
6B/H6 ( Grades: 9-12 ): Following fertilization, cell division produces a small cluster of cells that embeds itself in the wall of the uterus. As the embryo develops, it receives nourishment and eliminates wastes by the transfer of substances between its blood and the blood of its mother.
6C/H1 ( Grades: 9-12 ): The immune system functions to protect against microscopic organisms and foreign substances that enter from outside the body and against some cancer cells that arise within.
6C/H6 ( Grades: 9-12 ): The human body is a complex system of cells, most of which are grouped into organ systems that have specialized functions. These systems can best be understood in terms of the essential functions they serve for the organism: deriving energy from food, protection against injury, internal coordination, and reproduction.
6C/M1 ( Grades: 6-8 ): Organs and organ systems are composed of cells and help to provide all cells with basic needs.
6C/M2 ( Grades: 6-8 ): For the body to use food for energy and building materials, the food must first be digested into molecules that are absorbed and transported to cells.
6C/M3 ( Grades: 6-8 ): To burn food for the release of energy stored in it, oxygen must be supplied to cells, and carbon dioxide removed. Lungs take in oxygen for the combustion of food and eliminate the carbon dioxide produced. The urinary system disposes of dissolved waste molecules, the intestinal tract removes solid wastes, and the skin and lungs aid in the transfer of thermal energy from the body. The circulatory system moves all these substances to or from cells where they are needed or produced, responding to changing demands.
6C/M6 ( Grades: 6-8 ): Interactions among the senses, nerves, and brain make possible the learning that enables human beings to predict, analyze, and respond to changes in their environment.
6D/M3 ( Grades: 6-8 ): Human beings can detect a tremendous range of visual and olfactory stimuli. The strongest stimulus they can tolerate may be more than a trillion times as intense as the weakest they can detect. Still, there are many kinds of signals in the world that people cannot detect directly.
6E/H1 ( Grades: 9-12 ): Some allergic reactions are caused by the body's immune responses to usually harmless environmental substances. Sometimes the immune system may attack some of the body's own cells.
NSTA National Science Education Standards
C.1.5 ( Grades: 5-8 ): The human organism has systems for digestion, respiration, reproduction, circulation, excretion, movement, control, and coordination, and for protection from disease. These systems interact with one another.