To write an equation that represents the height of Plant A after any number of months, we start with its initial height and add the growth over time.
The initial height of Plant A is 4 cm, and it grows at a rate of 2 cm per month. If we let \( t \) represent the number of months, the height \( h \) of Plant A after \( t \) months can be expressed with the following equation:
\[ h = 4 + 2t \]
Here, \( h \) is the height of the plant in centimeters, \( 4 \) is the initial height, \( 2 \) is the growth rate in cm per month, and \( t \) represents the time in months.