The chart below indicates the elements contained in four different molecules and the number of atoms of each element in those molecules. In the equations below, A represents a food substance, and B represents its completely digested end product. The diagram below represents a white blood cell engulfing some bacteria. The diagram below represents a unicellular organism. When a chemical is added to a slide containing a paramecium, the paramecium moves away from the chemical.
Plants bend toward light because cells on the dark side of the stem elongate.
They are secreted in one place and most often act at another. They are distributed by the nervous system. They are found only in vertebrates. They are secreted into specialized ducts for transport. Scientists have been able to produce mutations in plants by irradiating their seeds with gamma rays.