A state in which severe restrictions are placed on the activities of individuals and groups desiring to influence the allocation of values by the political system is best characterized as

Authoritarian

Explanation:

In an Authoritarian state usually called authoritarianism, virtually all powers are in the hands of a central government or body. Non dares to challenge, lack or minimum political freedom is given. The government or leaders are not very easy to change or removed and the government has almost and if not all the controlling power.its usually operates an autocratic, oligarchic or a military type of government.

answer; /// decreasing responsiveness to a stimulus to which one is repeatedly exposed;