What are two of the processes that move tectonic plates over the surface of the earth?
a. slab pull and crust conversion
b. connection and convection
c. plate movement and convection currents
d. ridge push and slab pull

What causes darkening of the skin as melanin production increases

20. in humans, freckles are dominant to no freckles. trey has no freckles and his wife anna grace has freckles, but her dad doesn't. they want to know what percentage of their kids would look like trey. show a punnett square to support your answer.

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?