The heart
Gracilis
The tongue and the facial muscles are used the most (provided you are not paralyzed, or suffer from a stroke). The heart is commonly used to answer this question, but it is also an organ.
Rats used in scientific research are commonly from the species Rattus norvegicus, the brown rat. These are specifically breed to be used in research. For medical trials, white mice are more commonly used as they have a physiology much closer to humans.
In humans this is considered a vestigial, or no longer needed/used. In many animals, the coccygeus muscle is used to wag their tails.
The vastus lateralis (outer thigh) because it is the largest.
I think its the visceral muscle
diaphram
the diaphragm is the muscle(s) that are most important muscle used in inspiration (inhalation)?
The 12 most commonly used Interjections:yesohyeahnoheyhihellohmmahwowouchhurray
what are the most commonly used price indexes
What is the most commonly used e-communication
Diaphragm