Why do your tears and blood taste salty?

Because you've got a little bit of the ocean inside you. The ocean was the home of the first plants and animals. When the creatures came ashore to live on land millions of years ago, they carried some of the sea within their bodies. That's why humans and other creatures have salty water in their bodies.

Microrganisms

Animals that live in fresh water are faced with a problem. They are surrounded by a lot of water. The call of their body are full of salts, so there is less water inside their cell membranes, water will always try to move into their body from the outside. These animals have to continually get rid of the excess water. The amoeba is one of the simplest living organisms. Unicellular (only have one cell). Since it live in fresh water, water is always passing across its cell membrane into the cell. The amoeba has to pump out this excess water, almost as though it was baling out a leaky boat! It has a special structure called a contractile vacuole that repeatedly fills with water, moves to the surface of the cell and pumps water out. Many larger animals have developed impermeable surfaces that reduce the amount of water entering their body. For example, fish are covered with scales that are impermeable to water. Even the human skin is relatively waterproof. This means that, if you sit in the both for a long time, thankfully your body will not swell up with water!