💧 WATER
What is the most important ingredient for life as we know it?
Liquid water.
Which gas supports respiration?
Oxygen
What is Earth's main source of energy?
The Sun.
Which planet is called the Red Planet?
Mars
How many exoplanets have been discovered?
More than 5,000.
What does water transport through living organisms?
Nutrients
Which gas helps stabilize Earth's atmosphere?
Nitrogen
What process uses sunlight to make food?
Photosynthesis
Which moon may have an ocean beneath its ice?
Europa
What are exoplanets?
Planets that orbit stars outside our solar system.
Why do scientists search for water first when looking for life?
Because life depends on liquid water and its chemical processes.
What harmful thing does the atmosphere protect us from?
Solar radiation.
What keeps Earth's temperatures "just right"?
Earth's distance from the Sun.
What is the habitable zone?
The distance from a star where liquid water can exist.
What four conditions are essential for habitability?
Liquid water, atmosphere, energy source, and the right distance from a star.
About what percentage of Earth's surface is covered by water?
About 70%.
Without air, where would life be impossible?
On land.
Besides warmth, what systems does solar energy drive?
Weather and climate systems.
Why can't Venus support life?
Because it has extreme heat, high pressure, and no liquid water.
What protects Earth from solar wind and cosmic radiation?
Earth's magnetic field.
Without liquid water, what cannot happen?
The chemical processes that build and sustain life.
Name two important jobs of Earth's atmosphere.
Supports respiration and protects Earth from harmful solar radiation.
What would happen if the Sun stopped providing energy to Earth?
Life would not survive because Earth would lose its main energy source.
Name two reasons Mars is difficult for humans to live on.
Very thin atmosphere, extreme cold, no stable liquid water, and high radiation (any two).
Name four reasons Earth is able to support life.