Why doesn't gravity pull water all the way to the center of the earth?

How has the scientific community addressed the safety of chemicals? a. chemicals are repeatedly tested, even those that have existed for a long time. b. existing chemicals are tested if they have never been tested before. c. chemicals are tested if they are suspected to have caused a problem. d. only new chemicals are tested.

The isotonic saline solution described in part a is connected to an unknown solution via a semipermeable membrane, the unknown solution level drops. based on this information, what can be said about these two solutions?

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space