This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: An electromagnetic wave refractor in some aperture antennas is a component which due to its shape and position functions to selectively delay or advance portions of the electromagnetic wavefront passing through it. The refractor alters the spatial characteristics of the wave on one side relative to the other side. It can, for instance, bring the wave to a focus or alter the wave front in other ways, generally in order to maximize the directivity of the antenna system. This is the radio equivalent of an optical lens. Question: What is used to allow one to control the function of wave fronts moving through an antenna?
selectively delay

Passage: Tito's notable grandchildren include Aleksandra Broz, a prominent theatre director in Croatia; Svetlana Broz, a cardiologist and writer in Bosnia-Herzegovina; and Josip "Joška" Broz, Edvard Broz and Natali Klasevski, an artisan of Bosnia-Herzegovina. Question: Which of Tito's grandchildren is a cardiologist and writer?
Svetlana Broz

Passage: Once in Hollywood, the contestants perform individually or in groups in a series of rounds. Until season ten, there were usually three rounds of eliminations in Hollywood. In the first round the contestants emerged in groups but performed individually. For the next round, the contestants put themselves in small groups and perform a song together. In the final round, the contestants perform solo with a song of their choice a cappella or accompanied by a band‍—‌depending on the season. In seasons two and three, contestants were also asked to write original lyrics or melody in an additional round after the first round. In season seven, the group round was eliminated and contestants may, after a first solo performance and on judges approval, skip a second solo round and move directly to the final Hollywood round. In season twelve, the executive producers split up the females and males and chose the members to form the groups in the group round. Question: Which season did not have a group round in Hollywood?

seven