The structures whose movements are studied in mitosis and meiosis are called chromosomes.

Here's why:

* Chromosomes are the condensed, organized forms of DNA that become visible during cell division.

* Mitosis and meiosis are processes of cell division where the chromosomes are meticulously separated and distributed to the daughter cells.

* The movements of chromosomes during these processes are crucial for ensuring that each daughter cell receives a complete and accurate copy of the genetic material.

Let me know if you have more questions about mitosis or meiosis!