How do you classify the different biological zones in rivers and streams width wise?

As explained below.

Explanation:

A stream is a body of water with water on the surface flowing as in channels, beds, and banks. A stream can also include underground flowing stream and it responds to biological, geomorphological and hydrological biotic factors. As depending on the locations the longer streams are called rivers and form an important component of the hydrological cycle.  Types of streams ecological zones are a Brook, Creek, River, Tributary. Their sources may be in the form of ice, snow, rain or runoff. The ephemeral stream has a less floe and is generally formed from the rainfed water. Usually of low widths. The intermittent stream is a full flood stream with a high capacity of water and found in alpine sources. River gradient and age of the river also affects its carrying capacity.  As the younger and newer river flowing at the mouth have strong currents, as compared to the middle meandering river that is a mature and old stage of the river that tends to be lower gradient and depository in nature.

The answer is d if you are on edgenuity.