* not completed

. Which of these processes in the nitrogen cycle is/are true? (Please select all that apply)

Nitrogen fixation can be carried out by both biotic and abiotic processes correct incorrect

Combustion is a process by which nitrogen that was present in living matter is returned to the atmosphere correct incorrect

Ammonification is the process by which nitrate in soil is converted into ammonia correct incorrect

Denitrification can lead to the production of either N₂ (g) or N₂O (g) correct incorrect

Nitrification is an oxidation reaction where ammonium is converted to nitrate correct incorrect

* not completed

. Which of these processes in the nitrogen cycle is/are true? (Please select all that apply)

Nitrate does not take part to a significant extent in exchange reactions with soil solids correct incorrect

Ammonium ion mobility in soils is controlled only by geochemical processes correct incorrect

Acidity in soils is balanced to some extent by ammonium uptake correct incorrect

Nitrification is an acid generating process correct incorrect

Nitrate assimilation is an acid neutralizing process correct incorrect

* not completed

. Which of the following soil components cannot act as an electron acceptor in microbiological reactions? (Please select all that apply)

SO₄^2- correct incorrect

O₂ correct incorrect

NH₄⁺ correct incorrect

H₂O correct incorrect

Fe(OH)₃ correct incorrect

* not completed

. Which of these statements about oxygen and the carbon cycle is/are true? (Please select all that apply)

As algae grow during daylight the oxygen content of the ambient water increases correct incorrect

The chemical oxygen demand (COD) is a measure of the organic matter content of a water body correct incorrect

The oxygen concentration in a lake is lower in the winter than in the summer correct incorrect

The terms anoxic and anaerobic both refer to the absence of O₂ in a water body correct incorrect

While photosynthesis is taking place, the pH of the surrounding solution decreases correct incorrect

* not completed

. Which of these statements regarding the sulphur cycle is/are true?  (Please select all that apply)

Sulphate and sulphide as soluble species or in minerals are the two most common forms of sulphur in aqueous systems correct incorrect

When sulphide species are oxidized, the pH of the surrounding medium goes down correct incorrect

The initial step in the decomposition of protein material in marine systems is the release of sulphur in the form of sulphate correct incorrect

Under low pE conditions sulphate can be reduced to form sulphide species correct incorrect

Reduced species of sulfur can move from water into the atmosphere correct incorrect

* not completed

. Which of the following statements about types of microbes is/are true? (Please select all that apply)

Algae play a role in converting inorganic carbon into organic forms correct incorrect

Fungi are usually found in aerobic somewhat dry situations correct incorrect

Bacteria require nutrients like nitrogen to convert carbonate species in water into organic forms correct incorrect

Actinomycetes are common in tropical grasslands correct incorrect

Bacteria are only found in aerobic environments correct incorrect

* not completed

. Which of the following statements about types of microbes is/are true? (Please select all that apply)

Fungi commonly act as degraders of organic material correct incorrect

Most bacteria are best adapted to living in acidic environments correct incorrect

Fungi numbers in soil are usually much greater than those of bacteria correct incorrect

Algae require warm temperatures in order to develop and grow correct incorrect

Protozoa are consumers of bacteria and other microorganisms correct incorrect

* not completed

. Which of the following statements about microbial activity is/are true? (Please select all that apply)

Fungi are a type of autotrophic microorganism correct incorrect

Facultative anaerobes require electron acceptors other than oxygen for oxidation correct incorrect

Heterotrophic microorganisms utilize inorganic carbon to synthesize new organic material correct incorrect

Leaf fall at the end of summer leads to an increase in the autochthonous population of microorganisms in the soil correct incorrect

All types of organisms require a temperature greater than 0^oC in order to survive correct incorrect

* not completed

. Which of the following statements about the carbon cycle is/are true? (Please select all that apply)

The greatest amount of carbon on the Earth's surface is in the form of plant biomass correct incorrect

Calcium carbonate can be precipitated from solution while photosynthesis is occurring correct incorrect

Redox buffered describes conditions where organic matter degradation is no longer possible correct incorrect

Biomass degradation is accompanied by a rise in pH correct incorrect

Carbon dioxide is released during anaerobic degradation of biomass correct incorrect

* not completed

. Which of the following statements about the nitrogen cycle is/are true? (Please select all that apply)

Denitrification is essentially the reverse reaction of nitrification correct incorrect

Uptake of nitrate by plants is an acid-neutralizing process correct incorrect

Ammonification is the reaction by which organic matter releases ammonium species during decomposition correct incorrect

Denitrification processes can contribute to climate change effects correct incorrect

Nitrogen fixation reactions have a positive free energy value correct incorrect