Although cooperation is currently the most popular paradigm in classrooms, competition has a number of advantages. Research on classrooms in which competition is encouraged has demonstrated that competition can increase motivation and productivity while s

The reading passage discusses three theories about how the moon was formed. However, the speaker in the lecture casts doubt on those proposals made in the article. He believes that all these hypotheses are not convincing. To begin with, The author asserts that the moon could have been formed when a piece of earth broke off from the Pacific Ocean basin due to high speed of earth's spinning. On the other hand, the lecturer refutes this claim. He indicates that this idea is faced with two problems. First, Findings show that the moon was hotter than the earth. Second, Rock samples from the moon reveal a different chemical composition than that of the earth. Moreover, the lecturer challenges the idea that the moon was born at the same time with the earth from the same nebula by aggregation of small particles to form a much larger body. Nevertheless, the professor in the lecture points out flaws in this argument. He states that the iron core in the moon is much smaller than the earth and accounts for only 25%. In contrast, the iron core of the earth constitutes 50% of the total mass. Finally, the excerpt posits that the collision theory could be true. It postulates that the moon was formed when a giant body, about the size of Mars, collided with the earth generating massive amount of debris, which finally coalesced to make the moon. This does not ring plausible for the lecturer. He poses the question why only one moon was formed, and not a group of moons. In addition, another question is why there is no chemical evidence for extreme evaporation due to this gigantic impact.