Can someone me with questions 15 to 17 plz.

All of the following are part of the biosphere except

Which change to the system wood cause the freely-moving piston to lower?

Scientists often have to deal with numbers that are either very large or very small. for example, the radius of the sun is approximately 696,000 kilometers, while bacterial cells are as small as 1.9 × 10-4 millimeters. express each number in an alternate form.