What type of colony is described as not touching any other colony?

An isolated colony is characterized by its separation from other colonies, meaning it does not touch or overlap with them. This isolation allows for the clear identification and examination of individual organisms, as each colony typically arises from a single progenitor cell, resulting in a distinct growth pattern. This is particularly important in microbiology when aiming to study specific bacterial species or strains, as it reduces the risk of contamination from other organisms, enabling accurate isolation and subsequent analysis.

The other types of colonies listed do not fit this definition since they imply some degree of contact or clustering among colonies. A clustered colony, for example, suggests the presence of multiple colonies that are in close proximity, while contiguous and grouped colonies also imply that colonies are touching or near one another. This distinction helps microbiologists effectively isolate and identify specific microbes for further study.