This is because twilight or mesopelagic zone (extending from 200 meters to 1,000 meters) is the zone that contains the thermocline.
A thermocline or the thermal layer is a layer in an ocean or lake where the temperature changes more rapidly with depth than in the other layers. The thermocline in twilight zone divides the upper mixed layer from the calm deep water below.
There are so many examples for that in different areas, like steroidal compounds experiment carried out in our lab recently.
Here's one link: hhttp://www.alfa-chemistry.com/products/steroidal-compounds-8.htm
Inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli. This is what happens in the alveoli during gas exchange
True because machines are a replacement that doesn't need a salary like a person would