Question

Match the freshwater zones with their inhabitants.

$\begin{array}{ccc}\text{Column I}& \text{Column II}& \text{Column III}\\ \text{(1) Littoral zone}& \text{(a) Dimly lit zone}& \text{(i) Fast swimmers}\\ \text{(2) Limnetic zone}& \text{(b) Shallow zone}& \text{(ii) Floating plants}\\ \text{(3) Profundal zone}& \text{(c) Open water zone}& \text{(iii) Heterotrophs}\end{array}$

• A. 1-b-i; 2-c-ii; 3-a-iii
• B. 1-a-i; 2-b-iii; 3-a-ii
• C. 1-c-iii; 2-a-ii; 3-b-i
• D. 1-c-ii; 2-b-i; 3-a-iii

Answer 1

The correct option is A 1-b-i; 2-c-ii; 3-a-iii

$\bullet$ Freshwater ecosystem is divided into three different zones based on the availability of light at different depths:

i) Littoral zone: The shallow zone near the shore. Organisms in this zone have well developed sight, dull and greyish bodies and are fast swimmers. E.g., Clams, insects, several crustaceans, etc.

ii) Limnetic zone: The open water zone, receives a good deal of light. Different types of floating plants like water hyacinth, wolffia, etc., are seen in this zone.

iii) Profoundal zone: The dimly lit and cold zone. Mostly heterotrophs are found in this region. Bottom dwellers, that live here are mostly scavengers and predators. E.g., Crustaceans, crabs, fishes, etc.