With slug slime. Yes, you heard right!
The "building material" of a snail shell consists of lime. Some snails can "dissolve" lime directly from the ground by treating it with their slime and then taking it up through the sole of their feet.
This means that our underwater civilization needs snails, just as humans need cows!
Source (in german)Like astronauts!
You have to eat oils and food in small bags, otherwise the whole house would not smell of food and instead our noodles would float around in the living room.
What a mess!.
Like electric eels!
Electric eels have organs that are capable of generating electricity by squeezing and relaxing their muscles.
But... how do they use it underwater?..
Like electric eels?... stop!
Electric eels are hurt by their own electricity! When hunting, they can injure themselves and their environment. They try to prevent the current from passing through their organs.
This means that we need long objects like rods to keep the electricity away from us. Another option would be stone channels as conductors or even cables made from shark eggs.
One of the materials that most resemble plastic or rubber is shark eggs. Their texture is very tough and elastic.