+ c b b.uhd.edu/webapps/assessment/take/launch.jsp?course_assessment_id=_163904_18_course_id=_67883_18.content id=_2791027_1&step=null Support * Question Completion Status: QUESTION 6 10 po Which operator is used to concatenate two strings? None of the choices QUESTION 7 10 po What do the following Java statements do to String variable text? text = text.substring(0,text.indexOf("world")) + text.substring (text.indexOf("world")+"world".length()); Removes the first substring "world" Doesn't change anything Replaces the substring "world" by "hello" Removes every substring "world" QUESTION 8 10 po which of the following lounctatamant ce the 7th character in the Stone wasabla mw. Strine and act in the sharwariables