Explanation:

Anaphase:
- During anaphase, the sister chromatids are pulled apart towards opposite poles of the cell by the spindle fibers.
- This results in the chromosomes becoming shorter and thicker as they are condensed and compacted for segregation.

Metaphase:
- In metaphase, the chromosomes align along the metaphase plate in the center of the cell.
- They are fully condensed and visible under the microscope, appearing as distinct structures.

Telophase:
- Telophase marks the end of nuclear division, with the chromosomes reaching the poles of the cell.
- The chromosomes begin to decondense and the nuclear envelope reforms around each set of chromosomes.

Interphase:
- Interphase is the longest phase of the cell cycle where the cell grows, carries out its normal functions, and prepares for cell division.
- The chromosomes are in their least condensed form during interphase, as they are in the form of chromatin and are not clearly visible.

In conclusion, chromosomes are shortest and thickest during anaphase as they are condensed for segregation. They are fully condensed and visible during metaphase, while in telophase, they start to decondense. In interphase, chromosomes are in their least condensed form as chromatin.