What compounds are not likely to have ionic bonds

The excretory system,need answers for all: )

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.

Is the flow of energy during vaporizing more like the flow during melting or during freezing