Answer:
The correct answer is D. A thermocline is an area where the temperature of the ocean sharply decreases.
Explanation:
The thermocline is the indication of a transition between two layers of water with different temperatures and densities, for example in lakes or oceans.
The water under the thermocline has a different temperature than the layer above. The density of water is non-linear with the temperature; water has its highest density at 4 ° C, at higher or lower temperature the density is lower, so that the layers only mix on the contact surface.
A thermocline is visually perceptible as a layer of turbid water with swirls. Divers see that a dust layer often develops on this dividing line. The thermocline can vary in thickness, depending on the temperature difference and the mobility of the water mass (completely stagnant water has a thinner thermocline).
In the oceans the permanent thermocline is at a depth of about 50-100 meters, above which the sun influences the temperature of the water. Below the thermocline, the temperature keeps falling with increasing depth, but this is much more gradual. In the oceans, 90% of the water is below the thermocline.
