The process of exchange of the genetic materials between any two non-sister chromatids of homologous chromosomes is referred to as crossing over. It's significances would include :

1.Helps in the process of evolution,

2. Helps in bringing genetic variation in organisms due to the genetic recombination of genes.

3. Crossing over frequency helps in the construction of genetic maps.

In mitosis, the prophase is further understood by dividing it into the given sub-stages:

1.Leptotene :

In this stage the nucleus enlarges in size in the chromosome. The chromosomes appear thin, thread-like and single-stranded in this stage. They have swollen or beaded structures along their length and their ends appear converged towards one side of the nucleus called bouquet.

2.Zygotene:

In this stage, the identical chromosomes come together and form bivalent or homologous pairs. Further, ...

1. Genetic material between the two growing cells is divided unequally.
2. Unequal division in amitosis causes specific irregularities in growth and metabolism.

Go (Gap 0) phase or Quiescent Phase is the resting phase in which the cell remains metabolically active but is neither dividing nor preparing to divide unless instructed to do so.

Germ or reproductive cells

Centrioles

The stage of cell division in which paired homologous chromosomes get shortened and thickened is prophase I of meiosis. During this stage, the chromosomes condense and become visible as distinct structures, allowing for the homologous chromosomes to pair up and exchange genetic material through a process called crossing over. The shortening and thickening of the chromosomes during prophase I is important for proper alignment and separation of the homologous chromosomes during subsequent...