You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
A_cappella

Context:
Contemporary a cappella includes many vocal groups and bands who add vocal percussion or beatboxing to create a pop/rock/gospel sound, in some cases very similar to bands with instruments. Examples of such professional groups include Straight No Chaser, Pentatonix, The House Jacks, Rockapella, Mosaic, and M-pact. There also remains a strong a cappella presence within Christian music, as some denominations purposefully do not use instruments during worship. Examples of such groups are Take 6, Glad and Acappella. Arrangements of popular music for small a cappella ensembles typically include one voice singing the lead melody, one singing a rhythmic bass line, and the remaining voices contributing chordal or polyphonic accompaniment.

Question:
Where does a cappella still maintain a heavy presence?

Christian music