The xylem in the vein of the leaf does what

Which of the following is not a main characteristic that scientists focus on when determining which kingdom an organism belongs to

Hemoglobin is the compound in red blood cells that carries oxygen to the body. the distribution of hemoglobin in women in g/dl of blood is approximately normally distributed with mean 14 and standard deviation 1. too little hemoglobin, and you're anemic. 2. too much, and (unless you live at high altitudes), you can have other problems.

What percentage of light hits earth's surface directly?