As an environment changes, and some organisms have a higer fitness than others, naturla selection acts directly on
A) exsisting traits
B) genetic material
C)individual organisms
D)future traits

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 are charcteristics of lithosphere?

Which is an example of a population?