Asphere made of steel is put in water and surprisingly it floats. develop a hypothesis to explain this observation.

you first have to set it up as a proportion which would be:

 x  =        15

1000     100

The answer would be 100x=15000 after cross multiplying

After you divide 15000 by 100 you get x=150

That means that 150 people didn't answer the phone.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

chert is a sedimentary rock composed of microcrystalline or cryptocrystalline silica. with this little bit of information, you can come to the conclusion that your answer is c.  

explanation: