What are two main functions of bacterial appendages?

Bacterial appendages primarily serve the functions of attachment and motility. These structures, which include pili and flagella, play crucial roles in how bacteria interact with their environments.

Attachment is facilitated by appendages like pili, which can adhere to surfaces and other cells. This ability to attach is vital for colonization, allowing bacteria to establish themselves in specific niches or environments. It's also involved in forming biofilms, which are communities of microorganisms that adhere to surfaces and are encased in a protective matrix, enhancing survival in various conditions.

Motility is primarily associated with flagella, which are long, whip-like structures that enable bacteria to move towards or away from stimuli (a behavior known as taxis). This movement is important for finding nutrients, escaping harmful substances, and colonizing new environments.

The other options, while they describe important functions in various biological contexts, do not specifically relate to the primary roles of bacterial appendages. Reproduction and energy production involve broader cellular processes, while digestion, nutrient absorption, protection, and communication are functions supported by other cellular structures and mechanisms within bacteria rather than their appendages specifically.