TASK DEFINITION: You are given a sentence and your task is to generate another sentence that supports the given input.
PROBLEM: pH pH is a measure of the hydrogen ion concentration in water.

SOLUTION: The concentration of the hydrogen ion in a solution can be calculated when the ph is known.

PROBLEM: but when the earth s surface reradiates energy back to space, a significant portion of this thermal radiation is absorbed and reradiated by the atmosphere s CO 2 molecules back to the earth s surface, incrementally warming the planet.

SOLUTION: Gases such as co2 and methane can trap thermal energy in earth's atmosphere before radiating it into space.

PROBLEM: Alone among the planets, the surface temperatures of Earth allow water to exist in all three states, solid (ice), liquid (water), and gas (water vapor).

SOLUTION:
Water exists on earth in three matter states states.