This is a quote from the book "The Virtue Of Selfishness" by Ayn Rand
... are the values its nature has set it to seek. Its life is the standard of value directing its actions. There are alternatives in the conditions it encounters in its physical background — such
as heat or frost, drought or flood — and there are certain actions which it is able to perform to combat adverse conditions, such as the ability of some plants to grow and crawl from under a
rock to reach the sunlight. But whatever the conditions, there is no alternative in a plant’s function: it acts automatically to further its life, it cannot act for its own destruction.
read full book