TASK DEFINITION: You are given a sentence and your task is to generate another sentence that supports the given input.
PROBLEM: Reversible reactions are symbolized in chemical equations by a double-headed arrow, but the standard remains to call the materials on the left the reactants and the materials on the right the products.

SOLUTION: Reversible reactions are indicated by opposite-headed kinds of arrows.

PROBLEM: Carbon Dioxide and water vapour are excreted from the lungs by a combination of exhalation and diffusion (explained on the respiration page).

SOLUTION: Ccarbon dioxide and water vapor that is produced by cellular respiration is released through exhalation.

PROBLEM: Fins are used by fish to move through the water but also to  steer, stop and maintain their position, the latter in conjunction with  the swim bladder.

SOLUTION:
Fish use some of their fins to propel themselves through the water and some of their fins to steer.

