Answer: Option B. -> Fragmentation  
:
B
Fragmentation is the first step of decomposition process of dead and decaying matter or detritus in an ecosystem. During the fragmentation of detritus, small invertebrate animals like earthworms and termites, called detritivores, feed on the detritus and then physically break down the organic matter into smaller fragments.

Answer: Option A. -> Total living material
:
A
Each trophic level in an ecosystem has a certain mass of living material at a particular time called as the standing crop. The standing crop is measured as the mass of living organisms (biomass)in a unit area. The biomass of a species is expressed in terms ofdry weight.Standing crop is the total biomass of an ecosystemat a given time.

Answer: Option C. -> fresh water ecosystem
:
C
In fresh water ecosystem or aquatic ecosystem, a food chain typically starts with phytoplankton and ends at large fishes. Phytoplankton although at the lowest trophic level and form the base, they have the least biomass and the biomass increases gradually towards the top of the pyramid which consist of the big fishes having maximum biomass in the entire food chain. Thus the pyramid of biomass is inverted.

Answer: Option C. -> Hydrarch succession
:
C
Based on the ecological habitats, ecological succession can be of three types hydrarch, mesarch and xerarch. Hydrarch succession takes place in wetter areas, mesarch in wet and marshy areas, whereas xerarch succession takes place in dry areas. However, the climax stage in both hydrarch and xerarch succession will ultimately lead to medium water conditions or mesic conditions i.e. neither too dry, nor too wet. For e.g. a forest

Answer: Option C. -> 100 units
:
C
At each trophic level 10 percent of the energy is transferred. This is known as the Lindema's Law of Energy Transfer. Vole is at the second trophic level in this food chain. Plants will take 1% of 100000 units, i.e., plants will have 1000 units of energy. When a vole eats the plants only 10 percent of the energy in plants will be transferred, i.e., 10 percent of 1000 units. So the vole gets 100 units of energy.

Answer: Option A. -> The pyramid of energy is inverted in ocean ecosystem.
:
A
The pyramid of energy is always upright irrespective of the type of ecosystem, because energy decreases from a lower trophic level to a higher trophic level. Pyramid of biomass and pyramid of number vary in structure depending on the type of ecosystem. For example, pyramid of biomass is inverted in an aquatic ecosystem but pyramid of biomass is upright in a terrestrial ecosystem.

Answer: Option B. -> 10%
:
B
Any energy transformation is governed by the second law of thermodynamics. It simply states that whenever energy is transformed, there is a loss of energy through the release of heat. Similarlyenergy is lost as heat when it is transferred between trophic levels like in a food chain/food web.This makes the flow of energy in an ecosystem unidirectional. The studies of transfer of energy in different food chains in a large number of ecosystems have revealed a uniform pattern, which is stated as the 10 per cent lawby lindemann.According to thislaw, only 10 per cent of the energy entering a particular trophic level of organisms is available for transfer to the next higher trophic level.

Answer: Option C. -> Biogeochemical cycling
:
C
A biogeochemical cycle is a pathway by which a chemical substance or elements moves through both biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) components of earth.