You are given a sentence and your task is to generate another sentence that supports the given input.

Ex Input:
Oxygen molecules pass from the air space of an alveoli into its capillary bed via simple diffusion -- oxygen concentration in the air is greater than it is in the bloodstream.

Ex Output:
Oxygen is transferred into the bloodstream by simple diffusion.

Ex Input:
Most ecosystems on Earth derive their energy either directly or indirectly through the Sun and the process of photosynthesis.

Ex Output:
Most of the energy used by living things comes either directly or indirectly from the sun.

Ex Input:
Gamma radiation is generated by radioactivity, the decay of radioactive (unstable) atoms both in Earth's crust and in the atmosphere, and in reactions caused by cosmic ray collisions with atmospheric constituents, as well as by the decay of elementary particles produced by these collisions.

Ex Output:
Radioactive atoms, nuclear explosions, and stars produce gamma rays