Under what circumstances can witnesses before congress legally refuse to answer questions

battle of saint-mihiel, (12–16 september 1918), allied victory and the first u.s.-led offensive in world war i. the allied attack against the saint-mihiel salient provided the americans with an opportunity to use their forces on the western front en masse.

explanation:

the constitution of the united states gave congress the absolute authority over immigration laws

answer: in october 1962, an american u-2 spy plane secretly photographed nuclear missile sites being built by the soviet union on the island of cuba. president kennedy did not want the soviet union and cuba to know that he had discovered the missiles. he met in secret with his advisors for several days to discuss the problem.

explanation:

the han greatly expands the chinese empire. the han dynasty retains the centralized bureaucracy and unified political system of the qin but adopts and grafts upon this the confucian view that government should be run by educated, ethical men.

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