Question

1 of 25

The mesopelagic zone refers to the ocean depths in which there is

enough light to support plant growth.

no light at all.

dim light, but not enough for plant growth.

enough light for primary production by bacteria.

dim light, but enough to support only some hardy plants.

Question

2 of 25

Where is the main thermocline located?

In the mesopelagic.

Above the mesopelagic.

Below the mesopelagic.

It varies since the thermocline disappears in the tropics.

It varies since the thermocline moves up and down in the water column depending on the amount of oxygen.

Question

3 of 25

Photophores are

specialized eyes.

buoyancy-regulating organs.

specialized jaws.

light-sensitive organs that lack the lens of true eyes.

light-producing organs.