Given the task definition and input, reply with output. This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

There were a number of avenues to upward social mobility and the achievement of nobility. Poland's nobility was not a rigidly exclusive, closed class. Many low-born individuals, including townsfolk, peasants and Jews, could and did rise to official ennoblement in Polish society. Each szlachcic had enormous influence over the country's politics, in some ways even greater than that enjoyed by the citizens of modern democratic countries. Between 1652 and 1791, any nobleman could nullify all the proceedings of a given sejm (Commonwealth parliament) or sejmik (Commonwealth local parliament) by exercising his individual right of liberum veto (Latin for "I do not allow"), except in the case of a confederated sejm or confederated sejmik.
What class was polands nobility?