<span>A reversible reaction is a chemical change in which the products can be converted back to the original reactants under suitable conditions.</span><span> In a reversible reaction, changing the reaction conditions e.g. concentration, pressure or temperature will change the net direction the reaction goes i.e. more to the right (forward) or more to left (backward).<span>It also means a reversible reaction does not go to completion in either direction and all components, original reactants or ensuing products, ALL co-exist in the reaction mixture (see notes on chemical equilibrium).</span></span><span><span>This means the reaction can go in either direction i.e.</span><span> <span>A + B ==> C + D or C + D ==> A + B</span></span></span><span><span>A reversible reaction is shown by the sign ,</span><span> <span>a half-arrow to the right (direction of forward reaction), </span><span>and a half-arrow to the left (direction of backward reaction).</span><span>It is really important you understand that the terms right & left AND forward & backward are used in the context of how the equation is presented.</span></span></span><span><span>Most reactions are not reversible (irreversible) and have the usual complete arrow only pointing to the right.</span> </span>
Plants use carbon dioxide, and put out oxygen, so it's like a cycle there. plants have roots to collect water from the soil around them. And they use the sun for energy.