<u>Calcium carbonate:</u>
The calcium carbonate is found in sea shells and the bones of sea creatures. And it is settled on layer of ocean. The pH level can be equilibrium with atmospheric 
. There is constant concentration of in the water.
The limestone and calcium carbonate is present in the rocks, streams, lakes is helps to maintain the constant pH in the minerals present in the rock react with excess acid in the water.
When the acids or bases react with the calcium carbonate ,there is the excess change in the pH. The mixture of calcium carbonate ions in the water to prevent the damage in acid rain.
The advantage that is conferred to algae and plants that have sporopollenin is that they have reproductive cells that are more resistant to desiccation. Remember that a sporopollenin is a polymer that is inert and makes up the outer layer of pollen grains and spores. Sporopollenin<span> is also found in the cell walls of several taxa of green </span>alga<span>, including Phycopeltis </span>
ATPA molecule is a molecule that transfers energy from the breakdown of food molecules to cell processes
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