Question

The first-rate pollution monitor is
A. Molluscs
B. Butterflies
C. Honey bee
D. Plants

Answer 1

Freshwater invertebrate animals that belong to the second-largest phylum of the animal kingdom are commonly used as biological indicators of pollution. They help in detecting and indicating the pollution levels in a particular place.

Complete answer:
The second largest phylum of the animal kingdom is mollusca and the organisms belonging to these phyla are of great importance. Mollusks such as freshwater snails and bivalves are commonly known as bioindicator organisms. These organisms can help in monitoring the effect of pollution in freshwater ecosystems such as ponds, lakes, etc. They can be effectively used as biological indicators in studies to check the effect of organic wastes as well as inorganic wastes. Several studies have been conducted to check the bioaccumulation and toxicity of metals in the freshwater ecosystem using freshwater molluscs. These freshwater molluscs have less motility and are large which makes them ideal models to be used as biological indicators of pollution. These molluscs are also known as freshwater gastropods. Some of them show torsion.

Hence, the correct option is A-Molluscs.

Note: The freshwater gastropods have apparent sensitivity and sessile nature and are commonly used as biological indicators of metal toxicity and pollution. They can accumulate high levels of toxic metals that can lead to several sublethal and lethal effects. These effects can be studied using these organisms that can help to reduce the pollution levels in the environment.