Requirements for Life on Earth

Name the top two most important things that make life on Earth possible

• atmosphere, humans

• water, oxygen

• gravity, oxygen

• animals, humans

Which of these characteristics determines if a planet will have temperatures that are suitable for life?

• The angle of tilt of its axis
• The distance or proximity to its star
• The amount of clouds in its atmosphere
• The number of volcanoes on its surface

Analyse the picture - what are the two products of the process called?

• water, sunlight

• carbon dioxide, oxygen

• oxygen, sugar

• water, sugar

What helps insulate a planet, holding in heat and preventing wide changes in temperature from day to night?

• Atmospheric gases, like CO2 and water vapor

• A terrestrial surface

• A magnetic field

• The distance from the Sun

Which choice best explains why liquid water is considered an essential characteristic for life?

• Humans drink water to stay alive

• Water is in a cycle on Earth

• The cells of all living things require water

• Water vapor in the atmosphere absorbs heat and insulates the planet