Pyrrhoea is caused by bacterial infections along with other factors, Diarrhoea by caused by rotavirus along with many other factors. Dysentery is caused by Entamoeba histolytica.

Correct Option: D

Pyrrhoea is caused by bacterial infections along with other factors, Diarrhoea by caused by rotavirus along with many other factors. Dysentery is caused by Entamoeba histolytica.

Only some bacteria and blue green algae (cynobacteria) have the capacity to fix atmospheric nitrogen.
• Bacteria: Azotobacter, Rhizobium, Frankia etc.
• Blue green algae: Nostoc, Oscillatoria, Anabaena etc.

Correct Option: B

Only some bacteria and blue green algae (cynobacteria) have the capacity to fix atmospheric nitrogen.
• Bacteria: Azotobacter, Rhizobium, Frankia etc.
• Blue green algae: Nostoc, Oscillatoria, Anabaena etc.

Some of the blue green algae can tolerate extremes of temperature due to presence of gelatinous sheath, and compactness of protein molecules in protoplasm.

Correct Option: D

Some of the blue green algae can tolerate extremes of temperature due to presence of gelatinous sheath, and compactness of protein molecules in protoplasm.

Sex-factor or F-factor in bacteria results in high frequency conjugation. It allows bacteria to produce sex pilus necessary for conjugation.

Correct Option: B

Sex-factor or F-factor in bacteria results in high frequency conjugation. It allows bacteria to produce sex pilus necessary for conjugation.

In (E.coli) double stranded DNA is present.

Correct Option: C

In (E.coli) double stranded DNA is present.