3. naturally occurring
4. fossilized plants or air bubbles ( probably the plants tho)
5. increased
6. the green house effect occurs naturally, it is being polluted both naturally and unnaturally, the unnatural pollution is contaminating our 'greenhouse" and that is horrible.<span />
Answer:
Soil is composed of small pieces of a variety of materials, so it is a heterogeneous mixture.
Explanation:
Sandstone is a clastic sedimentary rock.
Cells are so small so the surface area and volume of them can be proportional to each other. This helps with the efficiency of the cell's absorption and waste expulsion processes. Also by the cell's smallness, communication from the nucleus to other organelles is fast and the cell can be regulated while the conditions for diffusion are still ideal.