1. Frogs can absorb oxygen through their skin
You may know that frogs can breathe through their lungs. But, do you know? Frog skin can also absorb oxygen, which is why frogs can stay underwater for a long time without having to surface. The skin cells of frogs are rich in blood vessels and oxygen absorbing proteins, which can convert oxygen in water into oxygen that can be used by frogs.
2. Flames are composed of ions
Flame is a substance that we often encounter in our daily lives, but do you know the essence of flame? Flames are actually composed of ions, which are particles with positive or negative charges. In a flame, the oxygen in the fuel and air reacts to produce a large number of ions, which emit visible light and heat, forming the flame we see.
