Simple Diffusion Across the Cell (Plasma) Membrane. The structure of the lipid bi-layer allows small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules such as lipids, to pass through the cell membrane, down their concentration gradient, by simple diffusion.
<span>a. Cretaceous
</span>The continents began to drift apart by the end of the _______ period.
NOT:
b. Cambrian
c. Neogene
<span>d. Permian</span><span>
</span>
The correct answer would be D
Answer:
Marble is a metamorphic rock.
Explanation:
Metamorphic rocks were once igneous or sedimentary rocks, but have been changed as a result of intense heat and/or pressure within the Earth's crust. They are crystalline and often have a “squashed” texture.
