In fact, to say that the forward reaction and reverse reaction are not both active simultaneously may not be entirely accurate.

Plants carry out the forward reaction getting the energy from sunlight.

The propulsion forces are the forward reaction of the water on the oars while in the water.

Again, high pressures will slow down the forward reaction.

So, in the beginning a reaction may have a very fast rate of forward reactions.

For similar reasons, lower temperatures would favor the exothermic forward reaction, and produce more products.

As a result, the reverse reaction speeds up more than the forward reaction.

The forward reaction as shown above occurs spontaneously and not the reverse.

In other words, the rate of the forward reaction is equal to the rate of the reverse reaction.

For every forward reaction molecules of A are destroyed.