Does a defendant have a right to refuse to answer any questions?

question .... Defendant did not assert a right to refuse to answer any questions, ask that the questioning come to a halt, or request counsel. Instead, he was showing that he knew he could refuse to answer any or all questions and would exercise this right on a question-by-question basis." ( Id . at p. 510, 122 Cal.Rptr.2d 285, 49 P.3d 1032 ; accord, People v. Silva (1988) 45 Cal.3d 604, 629630, 247 Cal.Rptr. 573, 754 P.2d 1070 ["A defendant may indicate an unwillingness to discuss certain subjects without manifesting a desire to terminate an interrogation already in progress "].)