In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

[Q]: Antigens illicit the release of what in the body?, Context: The humoral (antibody) response is defined as the interaction between antibodies and antigens. Antibodies are specific proteins released from a certain class of immune cells known as B lymphocytes, while antigens are defined as anything that elicits the generation of antibodies ("anti"body "gen"erators). Immunology rests on an understanding of the properties of these two biological entities and the cellular response to both.
[A]: antibodies

[Q]: What is sometimes combined with an RPG tube to keep from harming the user?, Context: Rocket-propelled grenades can beand often areused against hovering helicopters (e.g., by Somali militiamen during the Battle of Mogadishu (1993)). Firing an RPG at steep angles poses a danger to the user, because the backblast from firing reflects off the ground. In Somalia, militia members sometimes welded a steel plate in the exhaust end of an RPG's tube to deflect pressure away from the shooter when shooting up at US helicopters. RPGs are used in this role only when more effective weapons are not available.
[A]: a steel plate in the exhaust end

[Q]: when were Leon and Galicia reunited?, Context: After annexing the County of Portugal into one of the several counties that made up the Kingdom of Asturias, King Alfonso III of Asturias knighted Vimara Peres, in 868 AD, as the First Count of Portus Cale (Portugal). The region became known as Portucale, Portugale, and simultaneously Portugalia the County of Portugal. Later the Kingdom of Asturias was divided into a number of Christian Kingdoms in Northern Spain due to dynastic divisions of inheritance among the kings offspring. With the forced abdication of Alfonso III "the Great" of Asturias by his sons in 910, the Kingdom of Asturias split into three separate kingdoms of Leon, Galicia and Asturias. The three kingdoms were eventually reunited in 924 (Leon and Galicia in 914, Asturias later) under the crown of Leon.
[A]:
914