Polluted water bodies possess high algal growth due to the presence of nutrient. These nutrients increase the rapid growth of water plants, i.e., algae especially Nostoc and Oscillitoria, etc., and result in colonies. These colonies are generally surrounded by a gelatinous sheath and furtherleads to the formation of blooms in water bodies.

Chemosynthetic bacteria are capable of oxidising various inorganic substances such as nitrates, nitrites and ammonia and use the energy released for their ATP production. So, they are autotrophs and not heterotrophs.

The common or vernacular names changes with the change in place, causing confusion regarding the identification of specific specimen, whereas the complex scientific names are in latin and universally accepted and understood. Hence, scientific names are preferred over the common vernacular names.

Viruses are considered as living when they are inside a host but outside any host they are referred to as non-living due to their

(a) inert nature

(b) inability to reproduce

(c) lack of cellular organisation

(d) inability for growth and cell division

These characters potraited by viruses make them identical to non-living organisms. Viruses are considered a connecting link between living and non-living organisms.

In the five kingdom classification given by Whittaker four kingdom belongs to eukaryotes, i.e., Protista, Fungi, Plantae and Animalia, except for the kingdom-Monera that belongs to prokaryotes.

Eukaryotic organism are those that possess

(i) An organised nucleus

(ii) Possess double envelop system

(iii) Presence of cell wall

(iv) Membrane bound organelles are present.