Answer:
For d I'm pretty sure its Organ System, I apologies if I am wrong
Answer:You didn't provide examples
Explanation: Groundwater can cause erosion under the surface as it moves through the soil. During the movement an acid is formed which what causes erosion and deposition.
Hope that helps
The early precambrian atmosphere consisted primarily of nitrogen and carbon dioxide with almost no oxygen.
<span>Today, the atmosphere contains about 20% oxygen, less carbon dioxide and similar amounts of nitrogen. </span>
<span>Photosynthetic green-leaf plants and trees are largely responsible for the change, converting carbon dioxide to oxygen.</span>