The items listed below were found in a science classroom. * a heart made of plastic with many of its parts labeled * clay formed to look like Earth and other planets * a giant plastic plant cell with removable cell parts These items are all examples of
OPTIONS:
- models
- experiments
- variables
- controls

models


During a lab investigation a scientist heats a solid substance. The scientist observes that the solid has two different melting points. The scientist is able to separate the two resulting liquids. Which statement best classifies the original solid substance?
OPTIONS:
- It was an atom.
- It was a mixture.
- It was an element.
- It was a compound.

It was a mixture.


If a neutral atom loses an electron, what is formed?
OPTIONS:
- A gas
- An ion
- An acid
- A molecule


An ion