In many freshwater ecosystems, the amount of inorganic nitrogen compounds available acts as a limiting factor for growth. In other words, producers are unable to grow as rapidly as they otherwise could, even when no other factor is limiting. Which statements about these ecosystems are correct?
- A1, 3 and 4 only
- B1 and 3 only
- C2, 3 and 4 only
- D2 and 4 only