These are signs of a chromosomal abnormality. In this specific case, Down syndrome.
I think it might be flexing. First you tense, which is the flex, then you relax.
The root word which means "red" is a. erythr/o.
Just think about biology - you should know that red blood cells are called erythrocytes, where you can obviously see that root word.
Leuk/o refers to white color, and the other two options do not refer to colors at all.
