Arakan Yoma is the extension of the Himalayas located in (D) Myanmar. The Arakan Yoma mountain range runs through the western part of Myanmar (Burma) and extends into southeastern Bangladesh.

The land of white elephants is (C) Thailand. This term is often used metaphorically to refer to Thailand, highlighting its cultural richness and uniqueness. In Thai culture, the white elephant is considered a symbol of good luck and prosperity.

(A) Species that are found only in some particular areas

Endemic species are those that are native and restricted to specific geographical areas and are not naturally found anywhere else in the world. They have evolved and adapted to particular local conditions, making them unique to those specific regions.

The largest lake in the world by both area and volume is (A) Caspian Sea. The Caspian Sea, although called a "sea," is technically the largest lake on Earth. It is located in Central Asia and is bordered by five countries: Russia, Kazakhstan, Turkmenistan, Iran, and Azerbaijan. The Caspian Sea has significant economic and environmental importance for the surrounding regions and plays a crucial role in the geopolitical landscape of the area.

The decayed remains of living organisms in soil are called (B) Humus. Humus is the organic material that forms as a result of the decomposition of plant and animal matter. It is a dark, nutrient-rich component of soil and plays a vital role in soil fertility. Humus improves soil structure, retains moisture, and provides essential nutrients for plant growth. It is a key element in sustaining healthy and productive soils in various ecosystems.

The sea that does not belong to Russia is (B) Baltic Sea. The Baltic Sea is located in Northern Europe and is bordered by several countries, including Sweden, Finland, Denmark, Germany, Poland, Latvia, Estonia, Lithuania, and Russia. It is not entirely enclosed by Russia. The other seas mentioned (Laptev Sea, Kara Sea, and White Sea) are all located in the Arctic and subarctic regions and are part of the Russian territory.

Downs grasslands, commonly known as "downs," are extensive grassy plains found in Australia. These grasslands are a distinctive feature of the Australian landscape, characterized by vast expanses of open grassy areas. They play a crucial role in supporting unique ecosystems and biodiversity in Australia. Downs are often associated with pastoral activities and are utilized for grazing livestock, especially in regions with a semi-arid to arid climate. These grasslands contribute to the ecological diversity of the Australian continent.