The question asks about ecological pyramids and which type is always upright. We need to understand the concept of ecological pyramids (pyramid of numbers, biomass, and energy) and their characteristics, specifically whether they can be inverted or are always upright.
C) Pyramid of energy — The pyramid of energy is always upright because energy flows unidirectionally from producers to consumers, and a significant amount of energy is lost as heat at each successive trophic level. This loss ensures that less energy is available at higher trophic levels, preventing inversion.
The question asks to identify decomposer organisms from the given list. Decomposers play a crucial role in ecosystems by breaking down dead organic matter, returning nutrients to the soil. We need to evaluate each option based on its biological classification and ecological function.
Correct Option: B) 2 and 3 only
The question asks us to identify the correct statements regarding food chains in ecosystems. We need to evaluate each statement based on the definition and characteristics of a food chain.
A) 1 only
Statement 1 correctly defines a food chain as the sequence of organisms feeding on each other, representing the flow of energy in an ecosystem.
The question asks about the ecosystem where the pyramid of biomass is inverted. An inverted pyramid of biomass means that the biomass of producers is less than the biomass of primary consumers, which is less than the biomass of secondary consumers, and so on, at any given time. We need to identify which ecosystem typically exhibits this characteristic.
Correct Option: C) Aquatic ecosystem
The question asks to identify which option is NOT a type of ecological pyramid. Ecological pyramids are graphical representations showing the relationship between different trophic levels in an ecosystem. They can represent various ecological parameters.
Correct Option: A) Pyramid of time is not a type of ecological pyramid. Ecological pyramids are graphical representations of trophic structures, measuring parameters like number of individuals, biomass, or energy content at successive trophic levels, not time.
The question asks to identify which of the given organisms are used as biofertilizers. We need to recall the characteristics and applications of each organism listed.
B) 2 only. Nostoc is a cyanobacterium capable of atmospheric nitrogen fixation, making it a valuable biofertilizer, particularly in paddy fields.