The presence of limestone<span> and other calcium carbonate rock in </span>lakes<span> and streams helps to maintain a constant pH </span>because<span> the minerals react with the excess </span>acid<span>. However, </span>acid rain<span> eventually can overcome the buffering capacity of the surface water.
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4/4 100%
Because this means both parents are 50%
A single species that has evolved into several different forms that live in different ways has undergone "b. convergent evolution" since the multiple "divergent" species are seen to "converge" into a single species if you go back far enough in time.
