Answer: Option B. -> Energy
Answer: (b)
Ecosystems contain essentially two kinds of commodities: matter (nutrients) and energy. Material nutrients cycle through the biotic and abiotic parts of the ecosystem, available for repeated use by the organisms in the ecosystem's community.
However, energy enters an ecosystem by being used to convert low-energy carbon dioxide into high-energy carbohydrate, then passes through one or more of the organisms of the community, and is then lost to the ecosystem.
Eventually, all of the energy that enters the ecosystem is lost in the form of heat.

Answer: Option C. -> Tropical deciduous forests
Answer: (c)
The tropical and subtropical dry broadleaf forest biome, also known as tropical dry forest, is located at tropical and subtropical latitudes. Deciduous trees predominate in most of these forests, and during the drought, a leafless period occurs, which varies with species type.
Teak and Sal, along with mango, bamboo, and rosewood, belong to the moist deciduous forests which shed their leaves in the dry season.

Answer: Option B. -> Volcanic eruptions
Answer: (b)Some of the natural sources of air pollution are ground dust, salt spray from oceans, volcanic eruptions, hydrogen sulfides from natural sources, etc. Large amount of gases and ash from volcanic eruptions blacken the skies and increase the background pollution levels for years.

Answer: Option B. -> traps the air and keeps them warm
Answer: (b)The fur of the animals living in colder regions traps the air and keeps them warm.

Answer: Option A. -> saving the ozone layer from destruction by reducting the use of CFCs
Answer: (a)
The Montreal Protocol on Substances that Deplete the Ozone Layer (a protocol to the Vienna Convention for the Protection of the Ozone Layer) is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances believed to be responsible for ozone depletion.
The treaty was opened for signature on September 16, 1987, and entered into force on January 1, 1989, followed by the first meeting in Helsinki, May 1989.

Answer: Option A. -> aquarium
Answer: (a)An artificial ecosystem is one created by people. You can create an artificial ecosystem in an aquarium or terrarium. Nathaniel Bagshaw Ward is credited as the inventor of the terrarium, which he accidently created in 1829.

Answer: Option D. -> 7
Answer: (d)
Although tropical forests cover less than 7% of the earth’s surface they are home to approximately 50% of all living things on earth.

Answer: Option A. -> understanding the delicate balance in the relative number of organisms
Answer: (a)
Ecological balance is a state of dynamic equilibrium within a community of organisms in which genetic, species and ecosystem diversity remain relatively stable, subject to gradual changes through natural succession.'
In other words, it refers to a stable balance in the numbers of each species in an ecosystem. So to maintain this balance, the delicate balance between the organisms constituting an ecosystem should be understood.

Answer: Option B. -> Ocean
Answer: (b)
An ecosystem can be natural or man-made, large or small, permanent or temporary, complete or incomplete. Natural ecosystem.
It is an ecosystem developed under natural conditions without any appreciable human interference. A natural ecosystem can be terrestrial (e.g., forest, desert, grassland) or aquatic (e.g., freshwater, lake, pond, river, sea). Oceans constitute the most stable ecosystem.

Answer: Option B. -> Endemic
Answer: (b)Endemism is the ecological state of a species being unique to a defined geographic location, such as an island, nation, country or other defined zone, or habitat type. Species found in such restricted geographical area are called endemic species.