A solar cell is made of two types of semiconductors, called p-type and n-type silicon. The p-type silicon is produced by adding atoms—such as boron or gallium—that have one less electron in their ...

Examples of multicellular organisms include animals and most species of plants. The following diagram shows the variety of human cell types.

The presence of two types of hair cells, the inner and outer hair cells, in the organ of Corti was appreciated nearly a 100 years ago but the function of the two has only become clear in the last 20 ...

All fuel cells have the same basic configuration, an electrolyte and two electrodes, but there are different types of fuel cells, based mainly on what kind of electrolyte they use. Many ...