The generation of biomass of heterotrophic (consumer) organisms in a system is termed:

1.	biogeochemical cycles	2.	net primary productivity
3.	gross primary productivity	4.	secondary productivity

In an open ocean, the pyramid of biomass is often inverted. How can this support higher trophic levels?

Converting nitrate to nitrogen gas by anaerobes like Pseudomonas is:

The highest net primary productivity per square meter is of:

A secondary consumer amongst the following is:

The productivity in an aquatic ecosystem is least likely to be limited by:

In an ecosystem which of the following can never by inverted?
1. pyramid of numbers
2. pyramid of energy
3. pyramid of biomass
4. all can be inverted

In boreal forests soils contain large amounts of carbon but the primary production is low compared to other types of forests. This can be explained by:
1. high rates of herbivory
2. slow weathering of rocks
3. periodic fires in the forests
4. restricted decomposition

The amount of water required for a crop plant to produce one kilogram of food is approximately:
1. 1 Kg
2. 10 Kg
3. 100 Kg
4. 1000 Kg

A herbivore eats 4,000 J of plant material. 2200 J is indigestible and is eliminated as feces. 1,600 J are used in cellular respiration. What is the approximate production efficiency of this animal?