Can the change in cyclin concentration during mitosis be explained by the fact that the cell divides in two and thus divides the material in the cell into two smaller volumes

No, because cell division is expected to decrease not only the net amount of cyclin molecules in daughter cells but also the volume of these daughter cells compared to the original parent cell, and therefore the concentration should be nearly equal.

Explanation:

When a cell divides to produce two daughter cells, the cell components including its previously duplicated genetic material (DNA), organelles, signaling molecules, fatty acids (lipids), proteins, etc., are distributed into daughter cells. These daughter cells have a smaller volume compared to the original parent cell. In consequence, the concentration of cellular components (including cyclin proteins) should be similar between parent cell and daughter cells.

the circled areas are referred to   as sunspots.   the sunspots are cooler than the   surrounding area.

sunspots are temporary phenomena on the photosphere of the sun that appear visibly as dark spots compared to surrounding regions. they correspond to concentrations of magnetic field flux that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere.