After phosphates and nitrates enter a water system, the steps of eutrophication include the rapid growth of algae, death of underwater plant species, depletion of oxygen in the water, and the death of fishes and invertebrates. The correct option would be B.
Eutrophication refers to the excessive enrichment of water bodies by nutrients such as phosphates and nitrates thereby facilitating the rapid growth of some aquatic species with negative effects.
Once a water body becomes excessively enriched with phosphates and nitrates, the following is a sequence of events that follows:
- Algal bloom: the nutrients facilitate the rapid growth of algae
- The bloom of algal species results in the death of underwater plants as a result of inadequate light.
- The death of the underwater plants and the accompanying microbial activities in decomposing them cause oxygen levels in the water to drop.
- Reduction in oxygen level causes fishes and other water invertebrates to die due to hypoxia
Therefore, the correct steps of eutrophication according to the illustration is IV, II, I, and III.
More on eutrophication can be found here: https://brainly.com/question/13232104
