During the Seder, near the end of the maggid, we learn about the manner in which the Korban Pesach, the matzah, and the maror were consumed. In reference to the latter two, the haggadah reads:
?זוֹ שֶׁאָנוּ אוֹכְלִים, עַל שׁוּם מָה…
…This we eat, with garlic?
Why were the matzah and maror consumed with garlic, and why is garlic not specified also for the Pesach?