The verbal phrase is Unlimited.
A colon suggests that there will be a list that will follow it. Using the words 'such as', 'for example', and 'including' in a sentence also directs the attention of the reader to a list. It will be redundant to use a colon after the word 'including' in a sentence.
Answer:
Humans were observed as if they were insects under a microscope.
Explanation: