Final answer:
The two separation forces that contribute to the shortening of MTs during Anaphase A are the disassembly of kinetochore microtubules and the disassembly at the centrioles or MTOCs.
Step-by-step explanation:
The two separation forces involved in the shortening of microtubules (MTs) during Anaphase A are the disassembly of kinetochore microtubules at their minus-ends and the disassembly that occurs at the centrioles or microtubule-organizing centers (MTOCs). As Anaphase progresses, the cohesin proteins degrade, allowing the sister chromatids to separate at the centromere. Subsequently, each chromatid, now an individual chromosome, is pulled toward the centrosome to which its kinetochore microtubule is attached, effectively separating them.