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

What does every plane have?, Context: Grey-box testing (American spelling: gray-box testing) involves having knowledge of internal data structures and algorithms for purposes of designing tests, while executing those tests at the user, or black-box level. The tester is not required to have full access to the software's source code.[not in citation given] Manipulating input data and formatting output do not qualify as grey-box, because the input and output are clearly outside of the "black box" that we are calling the system under test. This distinction is particularly important when conducting integration testing between two modules of code written by two different developers, where only the interfaces are exposed for test.
black box

Where did the Grynszpan family live after Hanover?, Context: After 1937 the Lord Mayor and the state commissioners of Hanover were members of the NSDAP (Nazi party). A large Jewish population then existed in Hanover. In October 1938, 484 Hanoverian Jews of Polish origin were expelled to Poland, including the Grynszpan family. However, Poland refused to accept them, leaving them stranded at the border with thousands of other Polish-Jewish deportees, fed only intermittently by the Polish Red Cross and Jewish welfare organisations. The Gryszpan's son Herschel Grynszpan was in Paris at the time. When he learned of what was happening, he drove to the German embassy in Paris and shot the German diplomat Eduard Ernst vom Rath, who died shortly afterwards.
the border

An object that is fixed in place and cannot move is said to be also what?, Context: The normal force is due to repulsive forces of interaction between atoms at close contact. When their electron clouds overlap, Pauli repulsion (due to fermionic nature of electrons) follows resulting in the force that acts in a direction normal to the surface interface between two objects.:93 The normal force, for example, is responsible for the structural integrity of tables and floors as well as being the force that responds whenever an external force pushes on a solid object. An example of the normal force in action is the impact force on an object crashing into an immobile surface.
immobile