Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways of leave out essential information. A. In any ecosystem, as the number of individuals in the same species increases, the rate of disease transmission slows down. B. Ecosystems that have a small number of different species tend to be disease-free, because the species' habitats are at a safe distance from each other. C. In ecosystems with many species, diseases spread more slowly because there are fewer individuals in a species and, as a result, the individuals are more widely scattered. D. The average distance between individuals in a species-rich ecosystem increases, so diseases are prevented from being communicated between species.