A product life cycle contains 4 steps which include:

1. Research and development this is where it is introduced.  

.2. Growth is the product grows.

3. Maturity is where the product reaches its full potential.

EXTENSION STRATEGY: Three things BMW could do to extend the life of their products could be the following:

bring out new models

add new accessories

cut prices of the car

4. Decline is where the product has no use anymore.