Which type of rock contains the most fossils, and why?

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -

1. which of the following transport mechanisms utilizes energy? a. osmosis b. diffusion c. facilitated diffusion d. endocytosis

Stem cells found adult tissue such as in bone marrow brain muscle skin and liver are only capable of what