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 or leave out essential information. A. Some of the earliest important examples of symbiosis – the close cooperation of two or more living things – occur in island communities. B. Symbiosis – the close cooperation of pairs or small groups of living organisms – is especially important in these island environments. C. The first organisms on these islands worked together closely in a relationship known as symbiosis, which is particularly important on islands. D. It is significant to note that organisms in the beginning stages of the development of island life cannot survive without close cooperation.