What is responsible for identifying foreign invaders and remains in the system for a long period of time?

The climax of the story “seventh grade” occurs when

Sailors went to special school to learn how to use the new technology that would them sail far distences. the school we know about was

Pj conducts an experimental study on the effects of soft music during high stakes science testing. he randomly assigns students at the school. in one condition he does not provide music for testing while in the other group he does provide the music. he administers a pretest at the beginning of the year and a posttest at the end of the year. pj’s design is best described as a: a.static group comparisonb. pretest-posttest control group designc.control-group-time-series designd. nonrandomized control-group pretest-posttest design