Carbon dioxide is a gas that scientists say is a major factor in the planet's rising temperatures.
(Carbon dioxide; is; a gas that scientists say is a major factor in the planet's rising temperatures) (scientists; say; is a major factor in the planet's rising temperatures) (a gas; is; a major factor in the planet's rising temperatures)
Carbon dioxide scientists a gas
is say is
a gas that scientists say is a major factor in the planet's rising temperatures
is a major factor in the planet's rising temperatures
a major factor in the planet's rising temperatures