Knowing the audience determines how much background information you need to provide about the subject for the readers to understand it. Consider the following passage:
Bulbous plants will not flower again unless their leaves, which manufacture starch and sugars through photosynthesis, have time to replenish the depleted food supply of the bulb for the coming year. To replenish they create embryos for the next year’s flowers and, in the case of corms, produce new corms to replace the old ones. This process continues for weeks after the flowers die. That’s why the foliage must never be cut until it has yellowed. (From
The Tulip World, "About Bulbs")
What kind of audience is implied here?