What is measuring the age of fossils in years called?

i think the answer is a.keratin is the pigment responsible for skin color.

passive transport is a movement of biochemicals and other atomic or molecular substances across cell membranes without need of energy input. unlike active transport, it does not require an input of cellular energy because it is instead driven by the tendency of the system to grow in entropy.

so, according to what that says, i believe it's hypertonic and hypotonic.

good luck!