Mitosis is the mechanism by which the chromosome content of a somatic cell (haploid or diploid) is kept constant through successive cell divisions. The division of the cell is initiated by division of the nucleus i.e. Karyokinesis followed by division of cytoplasm i.e. Cytokinesis.

Astros are made up of microtubules. Microtubules are tubular structures that are made up of protein called tubulin. These tubules are the components of the cytoskeleton of the cell. They are involved in several processes such as cell division, intracellular transport, and maintenance of cell shape.

Microtubules are hollow, cylindrical structures that are composed of alpha and beta tubulin dimers. These dimers are arranged in a polar manner. The plus end of the microtubule is the end where beta tubulin is exposed, and the minus end is the end where alpha tubulin is exposed.

The microtubules are dynamic structures that undergo cycles of assembly and disassembly. The assembly of microtubules is regulated by microtubule-associated proteins (MAPs). These proteins interact with tubulin dimers and promote their assembly into microtubules. The disassembly of microtubules is regulated by depolymerizing proteins such as kinesins and dyneins.

In asters, microtubules radiate out from the centrosome, which is the microtubule organizing center of the cell. The centrosome contains two centrioles, which are cylindrical structures made up of microtubules. During cell division, the asters are responsible for positioning the spindle apparatus, which separates the chromosomes into two daughter cells.

In conclusion, asters are made up of microtubules, which are dynamic structures that are involved in several cellular processes. They are regulated by various proteins and play a crucial role in cell division.

The answer hidden in it's name 'Cyto' indicates cell as well as cytoplasm and 'kinin' indates division in plants cell, so by joining, it indicates Cell division in plants