The green seaweed Leticia imaginarium contains the compound DMSP. When herbivores graze on the seaweed, however, an enzyme converts the DMSP to DMS and acrylic acid. To determine the effect that these chemicals have on herbivores, researchers fed two herbivore species—a sea urchin (white bar) and a snail (black bar)—pellets containing no chemicals (the control), DMSP, DMS, or acrylic acid and recorded the amount of pellets that the animals ate. Considering the results in the graph, which, if any, of these chemicals appears to act a deterrent to snail herbivory?

MCQs on the field of Marine Biology, from a survey of the origin of oceans and their movements to details of marine food webs, life cycles, and marine zonation. As well as on marine environment and ecology, taxonomy and physiology, and contemporary concerns in the field, including human influences on marine systems.