Atmosphere & Hydrosphere
This term names the mixture of gases that surrounds a planet.
Atmosphere
The solid part of a rocky planet — rocks, soil, and landforms — is called this
Geosphere
Scientists make these to test ideas and represent natural processes that are hard to observe directly.
Models
This word means "having the conditions necessary to support life."
Habitability
All the liquid and solid water on a planet — oceans, rivers, ice — are part of this sphere
Hydrosphere
A long, narrow groove formed by flowing water or lava is called a ______
Channel
True or False: Models are exactly the same as the natural systems they represent.
False
All the living things on a planet together are called the ______
biosphere
On Earth, this process moves water from the surface into the atmosphere as vapor; it's a key part of the water cycle and important when considering past water on Mars.
Evaporation
When landforms on Mars look similar to those on Earth, scientists infer they may have been formed by the same _______.
geologic process
Give one example of how a model can help scientists study geological processes on Mars
Example: a flume to test sediment transport; a computer simulation of crater formation; a scaled-down lava flow experiment
Name the four "spheres" that interact to make up a planet system (as listed in the review)
Atmosphere, biosphere, hydrosphere, geosphere
Name two observations scientists might make about a planet's atmosphere that would suggest it once had more water at the surface.
presence of valley networks, mineral deposits formed in water (like clays), layered sediments or shorelines; any two reasonable observations
Describe one type of landform you might see that would provide evidence that water once flowed on Mars.
Example: sinuous channels, deltas, layered sedimentary rock, or rounded pebbles — any feature indicating flowing water
What does it mean when scientists say a model has limitations? Provide one specific limitation relevant to modeling Martian geology.
Sample: Models simplify reality and may omit key variables (e.g., gravity differences, exact material properties), so results may not fully match Martian conditions.
Explain why scientists study multiple spheres (for example, the atmosphere and geosphere) together when assessing whether Mars could have supported life in the past.