No Spain wasn't first to have slaves it was Europe who had the first slave's Hope this helps:)
The best theory to explain this reaction is the Lazarus theory of emotion. This theory indicated that emotions have a cognitive process; the emotions are valuations about the situations, depends on what we think about the situations to feel a determined emotion.
I hope my answer can help you.
Answer: 3) Confounding variable
Explanation:Confounding variable is the variable that indicates about the external influential factors that produces the manipulated consequences of independent and dependent variable.This variable can lead to producing useless outcomes in an experiment.
According to the question, the changes occurring in interest of student in algebra can be due to the outside factors which are not generating the actual results and thus, experiment is getting ruined.
Other options are incorrect because application variable remain same for the experiment,system variable are the variables of certain system and reliability variables describe about the variable on which dependent or stable.Thus, the correct option is option(3)
Answer:
b. to establish rules for european colonization of africa
