A scientist was interested in knowing how the amount of sleep a student gets the night before an exam affects the score that a student gets on the exam. He divided his subjects (students) into 3 groups. Group A took the exam after sleeping 6 hours. Group B took the test after sleeping 8 hours (normal amount). Group C took the test after sleeping 10 hours. He then looked at the test scores to see if there was any difference between the 3 groups. What is the independent variable in this experiment?

Use this dichotomous key for insect identification to identify the insect shown. 1. a. insect has one pair of wings. order diptera b. insect has two pairs of wings. go to #2 2. a. front wings thicker in texture than hind wings go to #3. b. front and hind wings are same texture throughout. go to #4 3. a. front wings are short order dermaptera b. front wings cover entire abdomen order coleoptera 4. a. wings with scale on all parts of their area. order lepidoptera b. wings without scales go to #5. 5. a. hind wings smaller than front wings. order ephemeroptera b. front and hind wings nearly equal in size. order odonata the insect pictured is in the order diptera. ephemeroptera. coleoptera. odonata.