The formal term for "guts" in a biological context is "intestines," which refers to the digestive tract's tubular structures. In a colloquial sense, "guts" can also refer to courage or bravery, but the anatomical term specifically denotes the internal organs involved in digestion.
Mother is the formal term for Mum
The formal term for a master's degree is a "postgraduate degree."
A declaration is a formal statement of opinion.
thereupon
amendment
myopia
Blacking out (less formal) or losing consciousness (more formal).
tier
Current events
symmetrical.
An argumentum is a formal term for an argument.
guts is a widely used term refering to the internal organs of an animal... sharks do have organs just like us humans. Very different organs but organs, so the answer would be yes.