Which factor is most responsible for the lack of plants in polar regions?

Low temperature is the most responsible factor for lack of plants in polar regions.

Explanation:

Due to extreme low temperatures in the polar areas, the soil in this area is completely frozen. In this case, the roots of the plants do not grow very deep. Therefore, there is little or no thick vegetation in this region.

The polar climate is a place where the available temperature is usually lower than cold, icy, snowy and does not get direct sunlight.  The Polar Regions, also known as frigid areas. These are planet regions that cover the geographical poles (north - Arctic and south - Antarctic) and are located in the polar Circle.

the cell theory states that all living things including animals, as well as plants, are made of cells.

answer; the above answer to the above statement is (true)