Tolong jelaskan mengenai Partisipasi dalam singel AKB48 dari Karen Iwata

NEW SHIP (GIVE ME FIVE!)

Ano Hi no Fuurin (Gingham Check)

Watashitachi no Reason (Eien Pressure)

Bara no Kajitsu (Sayonara Crawl)

Kaisoku to Doutai Shiryoku (Heart Electric)

Kiss made Countdown (Heart Electric)