题目内容：
种群密度有粗密度（或原始密度）和生态密度之分，按照生物实际占有的空间所计算的密度被称为__________。
参考答案：
选择题：种群密度有粗密度(或原始密度)和生态密度之分,按照生物实际占有的空间所计算的密度被称为_______
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