Each day the animals of the deep scattering layer
A) must form mucus nets to protect themselves from predators.
B) make a nocturnal migration to the DSL to feed.
C) make a nocturnal migration to the epipelagic to feed.
D) make a daytime migration to the epipelagic to feed.
E) migrate to a depth of 1.6 km to feed.

Question

Quizplus · Accepted Answer

The deep scattering layer (DSL) is located in the mesopelagic zone, which is below the epipelagic (sunlit) zone. Therefore, the animals of the DSL must make a nocturnal migration to the epipelagic zone to feed, as they cannot photosynthesize like the organisms in the epipelagic zone. Option A is incorrect because mucus nets are formed by some organisms in the epipelagic zone as a defense mechanism, not by those in the mesopelagic. Option B is incorrect because the animals of the DSL are already in the mesopelagic zone and do not need to migrate there to feed. Option D is incorrect because the epipelagic zone is where the animals of the DSL migrate to feed, and it is not a daytime migration. Option E is incorrect because 1.6 km is deeper than the mesopelagic zone where the DSL is located.

Each Day the Animals of the Deep Scattering Layer