Astronomers send probes to other planets to take pictures of their surfaces. An astronomer thinks that briny water flows on Mars because he noticed certain features in one picture of Mars. Which method did the astronomer use to form this hypothesis?
1.reading scientific literature
2.making careful observations
3. analyzing a natural experiment
4. conducting a controlled experiment

the volume of fluid displaced would equal the volume of the gas. use a gas syringe - this is a laboratory instrument that can be used to withdraw a certain volume of gas from a closed system or to measure the volume of gas from a chemical reaction.

shield volcanos are angry and get mad over the smallest things so much that there heads erupt   pahoehoe and a'a lava. a composite volcano is the poller opposite of a shield volcano. its   peaceful thing and knows how to control its emotions.