Final answer:
The combining form for 'viscer' is 'viscero-', used in medical terms related to the internal organs, such as in 'visceral reflex' and 'visceral muscle'.
Step-by-step explanation:
The combining form for viscer is viscero- which is used to denote a relationship to the internal organs of the body, commonly referred to as viscera. For example, in the word visceral reflex, which refers to an involuntary response of the internal organs, the prefix viscer(o)- is linked to the base 'reflex' to describe a reflex involving the viscera. Similarly, the term visceral muscle relates to the muscles associated with the internal organs of the body.
This combining form is often used in medical terminology to specify conditions, locations, or scientific descriptions that pertain to the internal organs.