They are considered so because are the indispensable parts of the nature cycle.Without formation,decay cannot be possible and similarly,formation cannot be possible without decay.In addition to this,THEY ARE IN A CHRONOLOGICAL MANNER SET BY NATURE and that's why cannot be seperated and so together constitute the cycle of nature.
The process of cellular differentiation is a direct result of a differiental
If two angles are supplementary to the same angles then they are congruent.
Metaphase. During metaphase, spindle fibers attach to the centromere of each pair of sister chromatids The sister chromatids line up at the equator, or center, of the cell. The spindle fibers ensure that sister chromatids will separate and go to different daughter cells when the cell divides