Answer : (a)

Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis. It is expressed in terms of weight (gm-2) or energy (kcal m-2). The rate of biomass production is called productivity. It is maximum where vegetation is maxiumum i.e., forest. Answer : (c)

Out of above options, Lizards are adapted to desert conditions. Thus, population of lizards is dominant in desert. Answer : (d)

Based on the source of their nutrition or food, organisms occupy a specific place in the food chain that is known as their trophic level. Answer : (c)

Energy flow is unidirectional. First, plants capture solar energy and then, food is transferred from the producers to decomposers. Answer : (a)

Nutrients such as phosphorus, oxygen, carbon, nitrogen are never lost from the ecosystems, rather they are recycled time and again indefinitely. The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmosphere, terrestrial, and marine ecosystems. Answer : (b)

The rate of biomass production is called productivity. Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis. Net primary productivity is the available biomass for the consumption to heterotrophs (herbiviores and decomposers). Secondary productivity is defined as the rate of formation of new organic matter by consumers. Answer : (a)

In forest ecosystem Pyramids, of number, of energy and biomass are upright, i.e., producers are more in number and biomass than the herbivores, and herbivores are more in number and biomass than the carnivores Answer : (a)

The domestic cooking gas cylinder contains LPG i.e. Liquid Petroleum Gas. LPG is extracted from crude oil and natural gas. Answer : (b)

In most ecosystems, all the pyramids, of number, of energy and biomass are upright, i.e., producers are more in number and biomass than the herbivores, and herbivores are more in number and biomass than the carnivores. Also energy at a lower trophic level is always more than at a higher level. In an ecosystem dominated by trees, the pyramid (of numbers) is of Inverted type because large population of birds and insects depends on small population of trees. The pyramid of biomass in sea is generally inverted because the biomass of fishes far exceeds that of phytoplankton. Pyramid of energy expresses mainly the amount of energy produced at a particular level. Answer : (c)

Based on the source of their nutrition or food, organisms occupy a specific place in the food chain that is known as their trophic level. Answer : (d)

Coralloid roots are specialized roots found in Cycas which are associated with nitrogen-fixing cyanobacteria. Cycads form mutualistic, facultative symbioses with nitrogen fixing cyanobacteria (blue-green algae). Answer : (c)

Net primary productivity is the available biomass for the consumption to heterotrophs (herbivores and decomposers). Secondary productivity is defined as the rate of formation of new organic matter by consumers. Answer : (d)

Rajasthan is a semi-arid to dry habitat area. There are desert in this state. Therefore, vegetation in Rajasthan is xerophytic. Answer : (a)

The pyramid of biomass in sea is generally inverted because the biomass of fishes far exceeds that of phytoplankton. Answer : (d)

A biocenosis, coined by Karl Möbius in 1877, describes the interacting organisms living together in a habitat. The use of this term has declined in the 21st сentury Answer : (b)

The rate of biomass production is called productivity. In forest ecosystems productivity is also high that contributes to maximum biomass. The reason for high productivity is greater number of trophic levels and inclusion of huge population of species is seen in this ecosystem. Answer : (d)

A savanna or savannah is a mixed woodland-grassland ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. Answer : (c)

Eugene P. Odum was an American biologist who gave the term ecosystem development to ecological succession. Answer : (a)

Taiga (North coniferous forests) are found above 5300 ft (1000-1500 m) altitude chiefly on mountains of Himalaya and Nilgiri. Answer : (a)

Pyramid of energy is always upright, can never be inverted, because when energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step. Answer : (a)

Coral reefs are among the most productive ecosystems on the planet, with the primary producers at the base of the food chain (including corals) supporting their complex food webs. Very low productivity is present in deserts and arctic regions. In oceans and other aquatic ecosystems, productivity is limited by light as it decreases with depth. An ecosystem of an agriculture land is called as agroecosystem. Sugarcane is the most productive agroecosystem. Answer : (d)

The factor that destroys plant biodiversity is destruction of habitats, wildlife species get extinct because of destruction of forest by deforestation. Answer : (d)

Starting from the plants (or producers) food chains or rather webs are formed such that an animal feeds on a plant or on another animal and in turn is food for another. The chain or web is formed because of this interdependency. Answer : (a)

The detritus food chain (DFC) begins with dead organic matter. It is made up of decomposers which are heterotrophic organisms, mainly fungi and bacteria. Answer : (d)

The reduction of nitrogen to ammonia by a living organism is called biological nitrogen fixation. Answer : (a)

Composition of living organisms, carbon constitutes 49 per cent of dry weight of organisms and is next only to water. Carbon cycling occurs through atmosphere, ocean and through living and dead organisms. Answer : (c)

Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis. A considerable amount of GPP is utilised by plants in respiration. Gross primary productivity minus respiration losses (R), is the net primary productivity (NPP). GPP – R = NPP Answer : (b)

Mulching is a simple process of using garden leftovers such as leaves, grass clipping & shredded trees to cover any bare soil in the garden. The main benefits of mulching are increased water retention, temperature control, and weed prevention. Answer : (a)

Mangrove forests, also called mangrove swamps or mangals, are found in tropical and subtropical tidal areas. Areas where mangroves occur include estuaries and marine shorelines. An estuary is a partially enclosed, coastal water body where freshwater from rivers and streams mixes with salt water from the ocean. Answer : (b)