sodium-potassium pump. n. The enzyme-based mechanism that maintains correct cellular concentrations of sodium and potassium ions by removing excess ions from inside a cell and replacing them with ions from outside the cell.
Answer:
A frogs heart has 3 chambers. Two atria and a single ventricle.
The atmosphere is a mixture because it contain many types of gases , liquids and solids.
Hadean is the first eon of precambrian, and took place around 4.6 and 4.0 billion years ago.
Radiation. hope that helped