Hello miss Linda

I really appreciate you explaning the topic thankyou very much

my question is

Why does stone (concrete) strong under compression ? can you explain me this

and

Why is Steel strong under tension ?

thank a mil

Well, stone is not always stronger under compression. If so rock crushers would not be able to break large hard quartz rocks easily. Laying that aside, metals like steel have great tensil strength. The molecules are bonded together in such an array that they very greatly resist separating, stretching, or breaking.
Concrete is somewhat compression resistant, however modern construction practices enhance this by including reinforcing steel (called re-bar). It act's somewhat like the bones in your body. The compression strength that concrete has derives from the energy of electromagnetic forces that bond cretain chemicals in cement (activated by water)to the agregate (small rocks) and sand in the concrete mixture.

Humm.
Try reading at the following sites:
http://en.wikipedia.org/wiki/Steel

And:

http://en.wikipedia.org/wiki/Concrete

My last attempt:

http://www.cement.org/basics/concretebasics_concretebasics.asp

(Broken Link Removed)