Fresh air contains approximately ______ percent carbon dioxide by volume.

In carbon cycle flow of energy is _________________

The reduction of sulphates and sulphites to hydrogen sulphide is done by which group of bacteria?

Which among the following develop in the upper portion of the Winogradsky column?

Which among the following is a non-sulfur purple bacteria?

The moisture contained in clouds and precipitated as snow,hail,rain etc constitutes _________________

Wells less than ___________ deep are considered to be shallow.

Hydrostatic pressure increases the boiling point of water but does not change the solubility of nutrients.

The degree of salinity in freshwater is nearly zero.

Protozoa and other minute animal life are known as ____________________

Phytoplanktonic organisms are non-motile.

Which of the following places shows the presence of Geothermal vents?

Most aquatic microorganisms can grow on the usual laboratory media.

Which of the following techniques is used for identification and enumeration of algae, bacteria, protozoa?

Which of the following zones have considerable rooted vegetation?

In which of the following seasons does the nutrient concentration falls at a drastically lower level?

The coastal adjunct of the marine ecosystem is __________________

In regions of the estuary that are nutritionally poor, it is more likely to find which of the following organisms?

The characteristic color of the Red Sea is associated with heavy blooms of __________________

Which of the following genus of bacteria is not found in fresh waters?

Which of the following aquatic organisms contribute in a small amount to the shallow estuary food web?