Which of the following statements about amphibians is true? A. Amphibians are represented by about 500 species of frogs, toads, and salamanders. B. Populations of amphibians in a few local areas have declined dramatically in the last few decades. C. Amphibians lay their eggs in dry, sandy areas close to a source of water. D. Their moist, absorptive skin makes amphibians very susceptible to environmental contaminants. E. Scientists increasingly perceive amphibians to be fair-weather species.

Apaleontologist finds a plant fossil that shows that the plant had seeds. what can the paleontologist conclude?

An animal cell (left) and a plant cell (right) are shown.which organelle, labeled x in the diagram, is found in both plant and animal cells?

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.