The difference between them is the Pure Sine Wave inverter produces a better and cleaner current. They are also considerably more expensive. You might find it practical to get a small Pure Sine Wave inverter for any special need you may have, and also a larger Modified Sine Wave inverter for the rest of your applications.
Elm Trees can live over 100 years in their natural environment.
Much like animals, the average age of trees depends on its species. If a tree has enough water, food and sunshine throughout its life, then it can live to the end of its natural lifespan. That said, no amount of care can make an elm live as long as a sequoia.