PLEASE HELPP I WILL GIVE BRAINLIEST

22mm²  

Explanation:

There are 6 sides of a "cell": 3 different types of sides with different dimensions that are multiplied twice because there is a front and back side with the same dimensions.

Front and back side = 2 × 5mm × 1mm

                                 = 10mm²

Left and right side = 2 × 1mm × 1mm

                              = 2mm²

Up and down side = 2 × 5mm × 1mm

                               = 10mm²

Total surface area = 10mm² + 2mm² + 10mm²

                              = 22mm²  

if you add everything up correctly you should get 69 i got this because 50 plus 19 is it