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The correct answer is Dead organic matter.

• Detritus food chain is the type of food chain that starts with dead organic matter.

Two type of food chains are found in nature-

1. Grazing Food Chain -

• The consumers starts with the food chain, utilising the plant as their food, constitute the grazing food chain.

2. Detritus Food Chain - 

• It starts from dead organic matter of decaying animals and plant bodies consumed by the microorganisms and then to detritus feeding organism called detritivores or decomposers and to other predators.

Key Points

• This dead organic matter gets decomposed by microorganisms.
• The organisms which feed on dead organic matter are known as detritivores as well as decomposers which in turn are eaten by the predators.
• Example-
• Dead organic wastes → Microorganisms → Decomposers
• In this representation, the food chain starts with the dead organic wastes.
• These wastes are consumed by microorganisms.
• These microorganisms are consumed by other detritivore organisms like snails, earthworms, etc.

The correct answer is Phytoplankton​.

Explanation:

• Some animals eat both plants as well as other animals, those who heart both are called omnivores.
• The omnivores eat plant food as well as the meat of other animals.
• Some of the examples are Man, dogs, crows, and ants.
• Man is called an omnivore because he eats both, plant food as well as the meat of animals.
• There is another type of producer and consumer who are extremely small.
• Planktons:
• They are very minute or microscopic organisms freely floating on the surface of the water in a pond, lake, river, or ocean.
• Planktons float near the surface of the water and provide food for many fish and other aquatic animals.
• There are two types of planktons:
• Phytoplanktons:
• The microscopic aquatic plants freely floating on the surface of the water in a pond, lake, river, or ocean.
• The free-floating alga is an example of phytoplanktons.
• Phytoplanktons are capable of producing food by the process of photosynthesis.
• Zooplanktons: ​
• The microscopic aquatic animals freely floating on water are called zooplanktons.
• The free-floating protozoa are an example of zooplanktons.
• A very, very small fish is also zooplankton.

Explanation:

• The ecosystem is characterized as a community of lifeforms that compete with non-living components and interacts with one another.
• Decomposers include saprophytes such as fungi and bacteria.
• Decomposers directly thrive on the dead and decaying organic matter.
• Decomposers are essential for the ecosystem as they help in recycling nutrients to be reused by plants.

Important Points

• Following is the role of a decomposer in the ecosystem:
• Decomposers act as a cleansing agent of the environment by decomposing dead plants and animals.
• Decomposers help in recycling the nutrients.
• Decomposers provide space for new being in the biosphere by decomposing the dead.
• Decomposers help in putting back the various elements into the water, soil, and air for the reuse of producers like crop plants.

Additional Information

Decomposers:

• The micro-organisms which break down the complex organic compounds present in dead organisms like dead plants and animals and their products like urine, etc., into simpler substances are called decomposers.
• Examples of decomposers are certain bacteria and fungi.
• The bacteria which act as decomposers are called putrefying bacteria.
• The decomposers help in decomposing the dead bodies of plants and animals and hence act as cleansing agents of the environment.
• The decomposers also help in putting back the various elements of which the dead plants and animals are made, back into the soil, air, and water for reuse by the producers like crop plants.
• It is only due to the presence of decomposers that the various nutrient elements which were initially taken by plants from the soil, air, and water are returned to the soil, air, and water, after the death of plants and animals.
• The decomposer organisms help in recycling the materials in the ecosystem so that the process of life may go on and on like an unending chain.

The correct answer is conservation of endangered plants and animals.

Key Points

• Convention on International Trade in Endangered Species of Fauna and Flora (CITES):-
• In order to regulate international trade in endangered species of Wild Life, the Convention on International Trade in Endangered Species of wild fauna and flora (CITES) was signed in March 1973.

Additional Information

CITES was conceptualized in 1963 at a meeting of the (IUCN) International Union For Conservation Of Nature.

• It came into force in 1975 and consists of 183 member countries to date that abide by CITES regulations by implementing legislation within their own borders to enforce those regulations.
• Located in Geneva, Switzerland, the CITES is administered by the United Nations under its UNEP (United Nations Environment Programme) Wing.
• The Convention of Parties to CITES is the supreme decision-making body of the Convention and comprises all its Parties.
• The last CoP (18^th) was held in Geneva, Switzerland 17 - 28 August 2019.
• India hosted CoP (3^rd) in 1981.
• Although CITES is legally binding on the Parties, it does not take the place of national laws.
• Rather, it provides a framework to be respected by each Party, which has to adopt its own domestic legislation to ensure that CITES is implemented at the national level.

Explanation:

• There are two basic conservation strategies, each composed of various techniques, that the conservationist can adopt to conserve genetic diversity once it has been located.
• The two strategies are ex-situ and in situ conservation.

Ex-situ conservation

• Ex-situ conservation means the conservation of components of biological diversity outside their natural habitats.
• Ex-situ conservation is the relocation of endangered or rare species from their natural habitats to protected areas equipped for their protection and preservation.
• It is an essential alternative strategy when in situ conservation is inadequate.
• Ex-situ techniques include seed storage, captive breeding, slow-growth storage, DNA storage.
• The main purposes of ex-situ collections are the rescue and preservation of threatened genetic material and the breeding of species for reintroduction in cases where a species’ continued survival in its native habitat is threatened.
• Ex-situ techniques applicable to animal populations include the storage of embryos, semen/ovule/DNA, or captive breeding through the establishment of field gene banks and livestock parks.
• Example- Zoo, aquarium, seed banks, botanical gardens, etc.

In situ conservation

• In situ conservation means the conservation of ecosystems and natural habitats and the maintenance and recovery of viable populations of species in their natural surroundings and, in the case of domesticated or cultivated species, in the surroundings where they have developed their distinctive properties.
• In situ conservation is the on-site conservation of genetic resources in natural populations of plants or animal species such as forest genetic resources, in natural populations of tree and animal species. The process of protecting an endangered plant or animal species in its natural habitat is commonly known as in situ conservation.
• Examples-
• Protected areas are the cornerstone of in-situ conservation.
• National parks, biosphere reserves, parks, sanctuaries.
• In-situ initiatives beyond protected areas may include
• Habitat restoration, recovery or rehabilitation.
• On-farm agricultural biodiversity conservation targeted at traditional crop varieties and crop wild relatives.
• Genetic reserve conservation, ie. monitoring of genetic diversity in natural wild populations within a delineated area.
• Control of threats to biodiversity such as invasive alien species, living modified organisms or overexploitation.
• Recovery programmes for nationally or sub-nationally threatened or endangered wild species.

Source -

https://biodiversitya-z.org/content/in-situ-conservation

https://biodiversitya-z.org/content/ex-situ-conservation

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/ex-situ-conservation#:~:text=The%20ex%2Dsitu%20conservation%20strategies,cultivated%20plants%20at%20low%20temperature.

Explanation:

There are basically two sources of energy:-

Wind energy – Non-Conventional.

Tidal energy - Non-Conventional.

Hydroelectric energy – Conventional.

Hence the correct option is hydroelectric energy.

Concept:

• Ecosystem: An ecosystem is defined as a community of lifeforms in concurrence with non-living components, interacting with each other."
• Types of Ecosystem:
• Terrestrial Ecosystem.
• Aquatic Ecosystem.
• ​The terrestrial ecosystem is exclusively land-based ecosystems. These are as follows:
• Forest ecosystem
• Grassland Ecosystems
• Tundra Ecosystem
• Desert Ecosystem
• An aquatic Ecosystem is a system that is present in a body of water. These are as follows:
• Freshwater Ecosystem eg: (river ecosystem), and (lake ecosystem).
• Marine Ecosystem eg: (oceanic ecosystem)

Explanation:

• Plankton, nekton and benthos are not the components of grassland ecosystem.
• As Benthos includes animals that are ecologically linked to the ocean's floor.
• Nekton includes aquatic animals that are able to swin and move independent of any water currents.
• Thus, Grassland ecosystems is the correct answer.

Key Points

Ecosystem: All organisms such as plants, animals, microorganisms and human beings as well as the physical surroundings interact with each other and maintain a balance in nature.

All the interacting organisms in an area together with the non-living constituents of the environment form an ecosystem.

Food chain: A food chain shows the feeding relationship between different organisms in a particular environment and/or habitat.

• A food chain shows how energy is passed from the sun to producers, from producers to consumers, and from consumers to decomposes such as fungi.
• They also show how animals depend on other organisms for food.

​

Only 10% of energy is transferred to higher levels from the previous one. So, the demand for food is more in higher levels. So, the food chain does not go for more than 3-4 tropic levels. This leads to more complex food forms known as a food web.

Primary (100%) → First level/ Primary (10%) → Second-level/ Secondary (1%) → Third level / Tertiary (0.1%).

Hence, when energy moves from one trophic level to another, it decreases

Explanation:

Rivers of Tripura:

Deo:

• Area: Jampui Hill, Dharmanagar, Kanchanpur valley.
• Flow towards: North. It meets the Manu river.
• Length: 132 km.

Dhalai:

• Area: Longtharai range, Khowai, Kamalpur.
• Flow towards: North to Bangladesh.
• Length: 117 km.

Gumti:

• Area: Longtharai, Amarpur, Gandachara, Udaipur, Sonamura.
• Flow towards: West up to Bangladesh.
• Length: 133 Km.

Haora:

• Area: Baramura range, Agartala.
• Flow towards: West up to Bangladesh.
• Length: 53 km.

Juri:

• Area: Jampui Hill, Dharmanagar Valley.
• Flow towards: North.
• Length: 79 Km.

Khowai:

• Area: Longtharai range, Khowai, Amarpur.
• Flow towards: North-west to Bangladesh.
• Length: 166 km.

Longai:

• Area: Jampui Hill, Dharmanagar.
• Flow towards: North.
• Length: 98 km long.

Manu:

• Area: Sakhan range, Longtharai, Kailashar.
• Flow towards: North to Bangladesh.
• Length: 167 km.

Muhuri:

• Area: Deotamura, Belonia.
• Flow towards: West to Bangladesh.
• Length: 64 km.

Feni:

• Originated at the border by the confluence of three streams.

Additional Information

Tripura:

• Tripura is the Northeastern state of India with its capital at Agartala.
• Manik Saha and Satyadev Narayan Arya are the incumbent chief minister and governor of Tripura respectively.
• Initially, Tripura was a category 'C' state and was granted the status of a Union Territory in the year 1956.
• Finally, it was raised to the status of a state on January 21, 1972.
• It is the only state of India which has been bordered from three sides by Bangladesh.
• It borders only one other Indian state and that is Assam.

Explanation:

Ecosystem: All organisms such as plants, animals, microorganisms and human beings as well as the physical surroundings interact with each other and maintain a balance in nature.

All the interacting organisms in an area together with the non-living constituents of the environment form an ecosystem.

Food chain: A food chain shows the feeding relationship between different organisms in a particular environment and/or habitat.

• A food chain shows how energy is passed from the sun to producers, from producers to consumers, and from consumers to decomposes such as fungi.
• They also show how animals depend on other organisms for food.

​

Only 10% of energy is transferred to higher levels from the previous one. So, the demand for food is more in higher levels. So, the food chain does not go for more than 3-4 tropic levels. This leads to more complex food forms known as a food web.

Primary (100%) → First level/ Primary (10%) → Second-level/ Secondary (1%) → Third level / Tertiary (0.1%).

Hence food cycle is the correct option.