John's parents would not let him study while listening to CD's in his room. They told Kim that he could not concentrate with the background noise. He decided to test this
idea with an experiment on his class. Each Friday his English class took a vocabulary
quiz on 25 new words learned that week. John got his teacher's permission to try his
experiment. On the first Friday of his test he played a rock song in the classroom
while the class took the test and the following week the class took the test with the
normal quiet atmosphere of a classroom. John calculated the average score on the two
vocabulary

This question is incomplete; the question is asking to identify the following: independent variable, dependent variable, control group, experimental group, and constants.

The answers are:

Independent variable- BACKGROUND NOISE/MUSIC

Dependent variable- AVERAGE SCORE

Control group- THE CLASS THAT TOOK THE TEST IN A NORMAL QUIET ATMOSPHERE

Experimental group- THE CLASS THAT TOOK THE TEST WHILE PLAYING A ROCK SONG

Constants- SAME VOCABULARY QUIZ, SAME NUMBER OF WORDS, SAME CLASS

Explanation:

Independent variable in an experiment is the variable that is manipulated or changed in an experiment. In this experiment, the independent variable is the MUSIC or BACKGROUND NOISE played during each vocabulary test.

The dependent variable is the variable that is tested or measured in an experiment. It is the variable that responds to changes made to the independent variable. In this experiment, the dependent variable is the AVERAGE SCORE on the vocabulary test.

Control group is the group that does not receive the experimental treatment. It is the group where the independent variable does not change in order to compare with the experimental group. The control group in this experiment is THE CLASS THAT TOOK THE TEST IN A NORMAL QUIET ATMOSPHERE.

Experimental group is the group that receives the experimental treatment. The experimental group in this experiment is THE CLASS THAT TOOK THE TEST WHILE PLAYING A ROCK SONG

The constants or control variables are the variables that are kept constant or unchanged throughout the experiment in order not to influence the experiment's result. In this experiment, the constants include; SAME VOCABULARY QUIZ, SAME NUMBER OF WORDS, SAME CLASS

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands