Mr. Doe wanted to perform an experiment to determine if doing a class review before a test would increase test scores. Mr. Doe normally does not review. To perform this experiment, Mr. Doe reviewed material with 2nd period before a test and did not review with 3rd period. After grading papers, he found that 2nd period had an average grade of 93 and 3rd period had an average grade of 72. He determined that reviewing before a test might increase test scores. 2. Which of the following is the control group?

Dr. kaylan is an ecologist who studies bird behavior. she sets up an experiment to test which type of food crows are most likely to eat when given a choice between walnuts, corn, and sunflower seeds. to perform her experiment, dr. kaylan places three food bins in an area frequented by cows. each bin contains one of the three food types. then, she measures how much of each food type is eaten every day for a month and summarizes the results of her experiment in the pie chart below. based on her results, dr. kaylan concludes that crows choose to eat corn more frequently than other food sources because it has a higher nutritional value. what is a reasonable alternate conclusion that can be drawn from dr. kaylan's data

Control of the body is accomplished by which of the following body systems? nervous system and circulatory system endocrine and repertory system circulatory and respiratory systems nervous system and endocrine systems

Give two examples of what would occur if one of the pairs did not match or had an extra chromosomes. explain how this might occur, and if it would be dangerous to the individual. fast.