Fragen über die Beispielsätze mit, und die Definition und Benutzung von "Clase"

A: clase muestra is 'class sample' - a sample of a class

with a bit of internet searching I think you might want to say

'sample type' (clase de muestra)

or 'class show'

If this is science related, it is most likely the 2nd option, if not I am happy to answer further questions despite my poor spanish skills

A: "Co-worker"/Compañero de trabajo.
"Classmate"/Compañero de clase.

A: What class are you in?

A: practice class?

A: I think it's "What type of camera did you use to take this photo/picture?" Not sure though ^^;