In cell biology, the spindle apparatus refers to the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells.It is referred to as the mitotic spindle during mitosis, a process that produces genetically identical daughter cells, or the meiotic spindle during meiosis, a process that produces gametes with half the number of ...

Background. Although related to the more general problem of the origin of language, the evolution of distinctively human speech capacities has become a distinct and in many ways separate area of scientific research. The topic is a separate one because language is not necessarily spoken: it can equally be written or signed.Speech is in this sense optional, although it is the default …