In order for two new cells to be created during mitosis, each cell must receive an identical copy of DNA. In order to accomplish this task efficiently prior to mitosis, a cell will condense DNA into

chromosomes

Explanation:

A cell must condense DNA into chromosomes before it can divide mitotically to form two new cells with identical copies of DNA.

The condensation of the DNA happens at the initial phase of the mitosis - the prophase - during which the DNA thickens and condenses to form chromosomes.

These chromosomes then align at the cell's plate during metaphase and they become separated into sister chromatids through the pulling of the spindle fiber at anaphase. Separated chromatids of the same chromosome are then transported to the opposite ends of the cell where they decondense before cytokinesis takes place.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.