What are three lines of evidence that support the hypothesis that our sea floor spreads apart at ocean ridges. name and describe in detail.

Sea floor spreading theory is given Harry Hess the line of evidence that support this are given as under.

Explanation:

Evidence from Molten Matter  

In the 1960s scientists found that there is a presence of new materials from below that need the lava to be uplifted and spread along the boundaries of mid-oceanic ridges i.e the lava or magma spreads through the active plate margins of both plates. The red sea is newly formed is an example of spreading, (a process of oceanic basin creation).

Evidence from Magnetic strips

The magnetism of the earth helped the scientists study the process of seafloor spreading as the newly formed lava gets deposited on either side of the ridges it takes the magnetic properties of the earth. The ocean floor is divided into strips of north and south after cooling.

Active and passive plate margins.  

The tri-junction of plates and newly discovered plate like that od red sea and splitting of the rift valley and transform faults. Movement of continents away from each other. Examples include Eastern pacific rise and Mid Atlantic ridge.

81 is a composite number.