Answer: Option D. -> Biological system
Answer: (d)
An ecosystem is a community of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment (things like air, water and mineral soil), interacting as a system.
These components are regarded as linked together through nutrient cycles and energy flows.
They are biological system in the sense that they represent recurring groups of biological communities that are found in similar physical environments and are influenced by similar dynamic ecological processes, such as fire or flooding.

Answer: Option D. -> climate and natural vegetation
Answer: (d)
A natural region is a basic geographic unit. Usually, it is a region that is distinguished by its common natural features of geography, geology and climate.
The surface of the Earth is divided into twelve natural regions. These regions have been categorized on the basis of surface features, climate and vegetation.

Answer: Option D. -> A living community and its environment
Answer: (d)An ecosystem is a community of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment (things like air, water and mineral soil), interacting as a system. These components are regarded as linked together through nutrient cycles and energy flows.

Answer: Option A. -> El Nino Modiki
Answer: (a)El Nino Modiki is associated with global warming.

Answer: Option D. -> Contour farming
Answer: (d)
The biological methods of soil conservation include contour farming, strip cropping, tillage operation, mulching, etc. Contour farming is practised in hilly regions or on the slopes.
The contours (circular or peripheral furrows) catch the downwardly moving water until it is absorbed in the soil. It reduces runoff, saves more water for crops, and reduces soil erosion.

Answer: Option D. -> soil, water and temperature
Answer: (d)
Soil, water and climate of a region are the three primary factors significantly influencing the vegetation of a region. Such factors as depth, texture, and humus content of the soil determine the type of vegetation that can be supported in a region.
Again, any vegetation needs moisture to survive and this explains the range which varies from evergreen forests to shrubs.
Temperature also plays a crucial role in plant growth and development with extremes on either end affecting plant growth severely.

Answer: Option A. -> Gonds
Answer: (a)
In paleo-geography, Gondwana, originally Gondwanaland, was the southernmost of two supercontinents that were part of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago.
It included most of the landmasses in today's Southern Hemisphere, including Antarctica, South America, Africa, Madagascar and the Australian continent, as well as the Arabian Peninsula and the Indian subcontinent, which have now moved entirely into the Northern Hemisphere.

Answer: Option C. -> Tundra
Answer: (c)
Polar climates feature long and dark winter periods with extremely cold temperatures. Rainfall is low, and the deeper soil layers stay frozen all year round.
These harsh conditions combined result in treeless, sparse vegetation, which includes shrubs, lichens and mosses, during the summer months. This typical vegetation linked to polar climates is called tundra.

Answer: Option C. -> biome
Answer: (c)Biome is a large naturally occurring community of flora and fauna adapted to the particular conditions in which they occur. For example, Tundra region.

Answer: Option D. -> Mercury
Answer: (d)Mercury causes biomagnification problem in the ecosystem.