Features that created suitable conditions

• Mass

  • great enough to prevent most gases from escaping
  • This atmosphere includes elements essential for life: carbon, hydrogen, oxygen and nitrogen.
  • Atmospheric pressure high enough to prevent all liquid water from boiling.
  • Water is vital as it is the general physiological solvent in which most biological reactions take place.
• Distance from sun

  • being too close or too far away from the sun would prevent liquid water being present.
  • Time taken for earth to rotate is fast enough to minimise excessive heating or cooling.
• Axis of rotation

  • axis is at an angle which produces seasonal variations
• Speed of rotation

  • 24-hour period of rotation reduces temperature extremes
• Magnetic field

  • deflects ‘solar wind’ and prevents biologically damaging radiation