Shades of blue show climate divisions that had monthly average temperatures below 50Â°F. The darker the shade of blue, the lower the average temperature. Climate divisions shown in shades of orange and red had average temperatures above 50Â°F. The darker the shade of orange or red, the higher the average temperature.
A stroma is the connective, part of a cell, organ or tissue. The  function of a stroma is to hold the cell, organ, or tissue together  and help it maintain form. Edit.
Stroma(noun) the connective tissue or supporting framework of an organ; as, the stroma of the kidney. Stroma(noun) the spongy, colorless framework of a red blood corpuscle or other cell. Stroma(noun) a layer or mass of cellular tissue, especially that part of the thallus of certain fungi which incloses the perithecia.