Birds are one of the most common animals we see, especially birds like sparrows, turtledoves, pheasants and magpies, which are often seen in flocks. However, one thing that is strange is that with so many birds, we rarely get to see bird nests, why is that?

Titan, a moon of Saturn, although it does not have a huge subglacial liquid water ocean like Europa, but this one planet also has a large number of lakes and oceans on its surface, which are not liquid water but liquid methane. Its atmosphere is also filled with gases like nitrogen and methane

Water bears are the common name for retarded animals, and these creatures are so small that their body length is usually no more than 1 mm, so we usually do not notice their presence.