Cockroaches, mosquitoes, flies, locusts, etc., have always been in the process of human evolution, and have been closely related to the history of the past. Even today, when science and technology are far more advanced than in the primitive human era, the main reason for the extinction of these ancient insects, which have evolved to perfection, is the change of climate and environment. Or a decrease in the amount of oxygen in the air.

Yun Lei took Rao Ya to walk through this jungle, but he could see that those dragonflies with a wingspan of about half a meter that were originally entrenched in this jungle slowly flew up and slowly left. Those mosquitoes the size of fists hovered beside the giant mushrooms, afraid to approach. Huge centipedes, which are between half a meter and a meter long, and things that look like scorpions and cockroaches, turn around and run.

There was not the slightest intention to attack Yun Lei and Rao Ya at all. Because the aura emanating from Yun Lei and Rao Ya was far stronger than them. The level of life is much higher than theirs. After sensing this breath, these insects, which have a certain ability to distinguish and perceive, naturally do not choose to kick the iron plate.

However, Yun Lei knew that these things were rare, so he caught a few of them of each kind and sent them back to the space gourd.

Naturally, Yun Lei and Rao Ya's so-called walking on the earth, it is unlikely that they will be like ordinary people, down-to-earth, one foot deep and one foot shallow, but will slide forward at a low altitude according to the direction of the ball's rolling and their own feelings. The two of them are now the existence of the Dan period. Naturally, you can fly through the sky.

Even in this underground world, he did not lose the instinct of a cultivator in the Dan stage.

It's going fast. In just an hour or two, it flew hundreds of kilometers. Although I don't know how big this huge underground space is. However, Yun Lei, with his intuition of space, sensed that the distance of hundreds of kilometers they flew out of was probably only one-tenth of the length or width of this incredibly huge underground space!

I am afraid that only in this way can this vast underground space reach an astonishing area of 100,000 square kilometers at the time of prediction.

After flying for hundreds of kilometers, Yunlei and Rao Ya traveled to the edge of a vast water. This water surface is vast and endless. Yun Lei and Rao Ya looked into the distance, but they didn't see the edge of this vast water.

Yun Lei suddenly remembered the information collected by the Gengzun about the underground world of the Tibetan Plateau in China.

According to the information collected by Yan Genzun -- in the mid-nineties of the last century, a scientific research team composed of scientists from all over the world used electromagnetic methods to arrange four ultra-wideband magnetotelluric deep detection profiles in the border of China, hoping to find the information fed back from the earth's interior.

Because there is a magnetic field on the earth itself, this kind of research and detection is still very effective. Some surprising data will be obtained.

These four ultra-wideband magnetotelluric deep detection profiles, from west to east, are distributed throughout the Tibetan Plateau, and as a result, through this detection, scientists have concluded that the crustal structure of the Tibetan Plateau in China is different. In the southern part of the Tibetan Plateau, from west to east, its conductivity is getting better and better, indicating that there is a mysterious substance with low resistance underground, and the further east, the larger the scale of this substance.

And this substance with excellent conductivity is most likely seawater, which is rich in electrolytes and salt!

In other words, under the Tibetan Plateau in China, it is quite possible that there is a vast underground ocean!

Now, this vast underground ocean, just before!

Yun Lei and Rao Ya stood in front of the vast underground ocean, breathing in the cold sea breeze. I was amazed by the magnificent scenery of the world in front of me. The water in this vast underground ocean still does not escape the gravitational pull of the moon and the sun, and still follows this gravitational pull, pulling the tide repeatedly.

When Yun Lei and Rao Ya arrived at the shore of this underground ocean, they saw that above the sea, there were layers of endless waves, surging towards the shore. Slapping on the shore and shattering into a cloud of spray. Little by little, it occupies the damp sand. I can see that this underground ocean is in the midst of high tide.

Of course, if there are just waves, tides, and underground, this is not enough to shock the well-informed Yunlei and Rao Ya. During this time, they can be regarded as well-informed. I've seen all the waves in the South Pacific, and these high tides are nothing.

What shocked Rao Ya and Yun Lei the most was that the sea water in the underground sea was actually all fluorescent!

Of course, it is impossible for seawater to emit light. It is the creatures in the sea that shine that shine.

In the ocean, there are actually many luminous creatures. Many single-celled organisms, deep-sea fish, and jellyfish, the body or a part of the body, emit light.

The only thing that can make seawater glow evenly is the multiplication of dinoflagellates single-celled organisms.

Dinoflagellates are a very primitive class of unicellular algae with many characteristics that fall somewhere between bacteria belonging to prokaryotes and protists belonging to eukaryotes. Currently, biology generally classifies it as a diflagellated algae.

Dinoflagellates are the body and are usually covered by a fibrous deck, and in the grooves formed between the decks, there are two or three flagella through which they can swim and feed in the water. The main feeding targets are some bacteria, cyanobacteria and unicellular algae.

The most common luminescent dinoflagellates, known as noctilucent insects. This dinoflagellates have a peculiar morphology, their algae are not covered by a deck, they are larger, usually lack chloroplasts, and rely only on their flagella to feed on prokaryotes or other algae. The root cause of its luminescence is the defense against some plankton.

After being stimulated by the external world, the nectilucent insect can produce electrochemical changes similar to the action potential of animal nerve cell membranes on the vacuolar membrane, which makes the voltage-sensitive proton channel on the vacuole membrane open, so that the protons in the vacuole can enter the small sac called the flash body on the vacuole membrane and activate the luciferase contained therein, thereby producing fluorescence.

These plankton, feed on dinoflagellates, however, when they prey on dinoflagellates, they emit fluorescence. Taking advantage of the phototaxic nature of fish, it attracts large fish that feed on plankton. Devour these plankton and thus gain their own living space.

Of course, for the Earth's oceans, the presence of fluorescent seas indicates that the bacteria and algae in the sea that can feed on dinoflagellates are overgrowing. This indicates that the oceans are polluted. Dinoflagellate is also the most important algae that forms offshore red tides. However, looking at this underground ocean now, it seems that there is no such trend.