The milk of many mammals contains cannabinoids, substances that are known to stimulate certain receptors in the brain. to investigate the function of cannabinoids, researchers injected newborn mice with a chemical that is known to block cannabinoids from reaching their receptors in the brain. the injected mice showed far less interest in feeding than normal newborn mice do. therefore, cannabinoids probably function to stimulate the appetite. which of the following is an assumption on which the argument depends? a. newborn mice do not normally ingest any substance other than their mothers' milk. b. cannabinoids are the only substances in mammals' milk that stimulate the appetite. c. the mothers of newborn mice do not normally make any effort to encourage their babies to feed. d. the milk of mammals would be less nutritious if it did not contain cannabinoids. e. the chemical that blocks cannabinoids from stimulating their brain receptors does not independently inhibit the appetite.

Astudent from one of the research labs is having trouble preparing a slide for examination and photographing. the bacterial slide that he has brought to you was prepared using a commercially purchased stain. he has asked for your in determining what he is doing wrong so that he can change the lab protocols and continue on with his project. after examining the slide under oil immersion, you determine that no bacteria are present even though the student is able to show you the culture he used to make that slide that has visible growth in the liquid medium. which of the following statements does not explain the fact that there are no bacteria present on the student’s slide? by not allowing a glass slide to completely air dry before heat fixation, the flame will cause the surrounding water to boil and this will damage the bacterial cell. overheating during the fixation step boiled the water within the bacterial cells and resulted in the cells bursting. insufficient heating of the slide did not drive out the thin layer of water and this resulted in minimal bonding between the bacteria and the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide.