"Human"

In fact, the earth's crust itself is a natural source of minerals, many soil and rocks contain a certain amount of salt, careful observation of cattle and sheep should know, cattle and sheep in the grass, but also often "eat soil" or lick the stone, they do so, in fact, the purpose is to obtain the salt

Intelligent life is rare in the universe, or perhaps it is just wishful thinking on our part. As mentioned earlier, just in the galaxy, there are hundreds of millions of planets that have the natural conditions to nurture life, so a reasonable speculation is that life has evolved on many planets, and even a number of planets have evolved intelligent life.

It is proposed that birds originated from dinosaurs, and that "ancestor birds" are a transitional species between birds and dinosaurs.

Since humans and chimpanzees are reproductively isolated from each other and cannot bond, can we transfuse chimpanzee blood to us humans?

When we humans feel very tired, we often say that we can fall asleep standing up, but this is just a description. In reality, it is impossible for humans to sleep standing up, but there are many animals in nature that have this such a skill that humans do not have, for example, horses can sleep standing up effortlessly.

The existence of reproductive isolation, so that these situations can not occur, even if there are some individuals of different species sometimes complete the mating, but they generally can not produce offspring, or produce offspring can not continue to reproduce

Theoretically, life can take many different forms, such as silicon-based life, sulphur-based life, carbon-based life, amino-life, hydrogen-based life, etc. However, so far we only know that life exists on earth, and all known life, including us humans, is carbon-based.

How exactly did such a complex life emerge on Earth? This is a great mystery to modern humans, but we are almost certain that the "birth of life" is a process that has a very small probability of occurring.

Of all the known rocky planets in the solar system, the one with the most similar natural environment to Earth is Mars, and exploration data show that Mars also has an atmosphere, four seasons of the year, and even a rotation period similar to that of Earth.