What is a stem cell?An embryo cellAn undifferentiated cellA differentiated cellAn adult cell

A stem cell is a unique type of cell with the capacity to develop into many different cell types in the body during early life and growth. Essentially, stem cells are undifferentiated cells that can divide and renew themselves for long periods. They are categorized mainly into two types:

1. Embryonic Stem Cells: These are derived from embryos and can turn into almost any cell type in the body, making them pluripotent. They play a crucial role in the early stages of development.

2. Adult Stem Cells: These are found in various tissues and serve to maintain and repair the tissue in which they are found. They are generally multipotent, meaning they can develop into a limited range of cell types.

In summary, stem cells are best described as undifferentiated cells capable of giving rise to specialized cells.