Decide whether or not the following experiment is internally valid. If not identify the source of threat to its internally validity. Professor Beach wanted to demonstrate to his cognitive psychology class how using retrieval cues can improve memory. First, he read a list of 16 words in random order to his class, and immediately afterwards he had them write down all the words they could remember. On average, they recalled about seven words. Then, he told them that the words could be sorted into four categories: automobiles, cutting instruments, sports, and fruits. Professor Beach encouraged his students to do this in their minds while listening to the list again, after which they would be given another chance to recall the words. On the second test of recall, students remembered, on average, 14 words. Professor Beach told his students that this proves the effectiveness of using retrieval cues as a mnemonic strategy.

Aunitary state is a form of state where power is concentrated and there is a single center of power that extends its actions throughout the territory of the respective state. this, through its agents and local authorities, delegates of that same central power, and in its majority; it can count on a single legislating apparatus; except for certain exceptions, which legislate for the entire country; a judicial power, which applies the current law to the entire territory of the state and within which a supreme court of justice is established, which has jurisdiction at the national level; a single executive power, that is conformed by all the governors (president, governors, mayors, etc.); and a single political constitution, which governs all the territory and to which all the authorities and inhabitants of the state are subject.a confederation (from the latin: confœderatĭo) consists of the union of states that retain their sovereignty and are governed by certain common laws. initially there was talk of "confederation" in the case of alliances, for this reason the word "confederation" is still used in non-governmental civil society institutions. for this reason, the term confederation is also used to describe any type of organization that combines the authority derived from other semi-autonomous entities. in this case, sports confederations can be cited as some examples. however, the word confederation takes much more relevance when it comes to some permanent alliance of states or some association or association of states.characteristics of a federal government system

  a) written constitution. also known as magna carta and a necessity of the democracies that form federations to regulate the principles by which the government will be governed, because if they had to act without a body of specific laws would produce confrontations.

b) territorial division. federalism is constituted by the division of powers on the geographical basis of each territory.

c) decentralization. in a federal system there is both a central government and units of government lower than the central one, each making decisions regarding the provision of certain public services in their respective geographical jurisdictions.

d) supreme court of justice. to counteract the rigidity of the written constitution, judicial action is required to interpret said constitution and necessary changes can be made.