Metals can be classified according to their chemical activity into three groups which are very active metals, less active metals, and inactive metals. The high reactivity of active metals makes them useful in a...
The fetus development the fertilization occurs about two weeks after the first day of the last menstrual period when the sperm penetrates the egg, and within 24 hours after the fertilization, the egg begins...
We must know the importance of echo in our life, There are many applications of echo in different fields whether scientific, technical or medical such as determination of the speed of sound through the...
The electric conductivity The substances can be classified according to the electric conductivity into good conductors of electricity and bad conductors of electricity, The electrical conductivity is the ability of a material to carry...
