How did the pebbles conglomerate become rounded?

What kind of threats do they pose to earth? Why can stars and planets not be seen on cloudy nights? Where are frame structures found? Who was killed for saying that the earth is round? What are the hardships of living on a volcanic island? Where does most digestion occur and how? Why does the Venus Flytrap snap shut when it senses an insect? Is a volcano a secondary succession or a primary succession? What receptor has a ligand that can cross the cell membrane that binds? In the experiment of anaerobic respiration of yeast what happened to the lime water or hydrogen carbonate indicator solution in it? Have binoculars changed over the years? What company makes tube expanders for medical plastic tubing? What is brightness adaptation? The most fundamental and important molecule that distinguishes living systems from non-living matter is? What do Mars' moons names mean? What statement can you make about the number of atoms in a relative mass of each type of atom? What is the time difference between Philladelphia and Athens? Which gas is responsible for the run-away greenhouse effect on Venus? How is energy transported from the core to the surface of the sun with radiation and by convection? How did geography affected the development of china?