.

1) Atom

2) Element

3) Molecule

4) Compound

Explanation:

An atom is a particle of matter that characterizes a chemical element. A compound is a substance that is made up of two or more different elements that are chemically joined, such as H2O,CO,NaCl. Note: All compounds are molecules, but not all molecules are compounds

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.

qualitative observation deals with data that can be observed with our senses: sight, smell, touch, taste, and hearing. they do not involve measurements or numbers. for instance, colors, shapes, and textures of objects are all qualitative observations.