A biome is a community of plants and animals that have common characteristics for the environment they exist in. They can be found over a range of continents. Biomes are distinct biological communities that have formed in response to a shared physical climate.

Equatorial type of climate, also known as tropi­cal rainforest wet climate , is located up to 5° to 10° latitudes on either side of the equator but at some places it extends up to 15°-25° latitudes mainly along the eastern margins of the continents.

The equatorial climate is found in the following localities:

(i) The Amazon Basin in South America,

(ii) The Congo Basin in Africa,

(iii) Guinea coast in Africa,

(iv) Much of the Indo-Malaysian Region mainly in Java, Sumatra, Bor­neo, Malaysia, Singapore and New Guinea,

(v) Philip­pine Islands,

(vi) Eastern central America (parts of Panama, Costarica, Nicaragua, Honduras, Guatemala etc.), some islands in the Caribbean Sea, western Columbia and eastern Madagascar.

Biomes are largely based on the geography and climate of a region. Therefore, a biome is a Geoclimatic zone that is identifiable on a global scale and includes things such as plants and animals.

Amazon basin is located in South America at 10° N and 10° S of the tropical region. This region is also referred to as the equatorial region. The Amazon river flows through the region and reaches the Atlantic Ocean through the mountains in the west.

The convectional rainfall occurs due to the thermal convection currents caused due to the heating of ground due to insolation.The convectional rainfall is prevalent in equatorial regions. In these, the warm air rises up and expands then, reaches at a cooler layer and saturates, then condenses mainly in the form of cumulus or cumulonimbus clouds. In the equatorial regions, the precipitation due to convectional rainfall occurs in the afternoon

Amra Vrushti.

Deforestation leads to a decrease in water holding capacity of the soil. The movement of water from the soil surface to the ground  may lead to floods.

The tropical rainforest is a hot, moist biome where it rains all year long. It is known for its dense canopies of vegetation that form three different layers

• Mt Cameroon is a volcanic mountain located in Cameroon near equator. It receives highest rainfall in the equatorial region.
• All the other options, viz Cherrapunjee,mawsynram(India) and Mt Waialeale(Hawaii,USA) are located near tropic of cancer, hence incorrect.

The equatorial region has hot wet and rainy weather.

The Turan Type of regions experience extreme climate. It stretches from the Caspian, eastward towards the Pamirs, and from the northern edge of the Plateau of Iran northward, beyond the Sea of Aral, to the Kirghiz steppes. The climate is continental, with hot summers, cool winters and a low rainfall. 

Island refers to the land which is surrounded by the water. Greenland is the largest island on the earth. It possesses the world’s second largest ice sheet. The total area of Greenland is 2,166,086 square kilometers. Geographically, it is closer to North America but it associates more with Europe. Greenland is the least densely populated country in the world. It has a population of around 56,000 people.

Caspian sea is the largest inland sea on the world with 40 to 44% of total lacustrine water of the world. It covers a area of 371,000km squre and located between Asia and Europe. Due to tectonic uplift it become landlocked about 5.5 million years ago.

A low-pressure area of calm, light variable winds near the equator is known as the doldrums, near-equatorial trough, intertropical front, or the Intertropical Convergence Zone. When located within a monsoon region, this zone of low pressure and wind convergence is also known as the monsoon trough.

• Sun rays fall vertically over the equatorial regions throughout the year thus they are hot. Also, they receive rainfall throughout the year, making them wet.
• Heavy rainfall leaches the nutrients from the soils of these regions thus they have low fertility.
• The high density of trees makes them compete for sunlight, which leads to trees growing up to great heights to receive sunlight.
• Thus all the options are correct. D is the right option.

Equatorial regions are the regions located on or near the equator. Equatorial regions have hot and wet climate. The Amazon Basin (South America), the Congo Basin (Africa), Malaysia, Indonesia and some areas in northern Australia are located in equatorial region. These regions do not have winter or dry season. The diurnal range of temperature is usually greater.

Rain forests include more than two-thirds of the world's plant species. These plants live in a warm humid environment. It allows enormous variation. There are so many flowering plants. Aerial plants are also found in rain forests. The humidity of rain forest encourages adaptations. Mahogany, ebony, green heart, etc. are the main trees found in rain forests.

The word arboreal originates from the Latin word “arboreus”. It means adapted to living on trees. This word not just refers to animals that live on trees but also to anything that resembles the branching form of a tree. Monkeys that are adapted to live on trees are also called arboreal.

Equatorial regions are the regions located on or near the equator. Equatorial regions have hot and wet climate. The Amazon Basin (South America), the Congo Basin (Africa) and some regions of Asia are located in equatorial regions. These regions do not have winter or dry season. The diurnal range of temperature is usually greater.

Equatorial regions are the regions located on or near the equator. Equatorial regions have hot and wet climate. The Amazon Basin (South America), the Congo Basin (Africa), Malaysia, Indonesia and some areas in northern Australia are located in equatorial region. These regions receives vertical sun rays. The climate in equatorial regions is characterized by heavy rainfall and constant high temperature. These regions do not have winter or dry season. The diurnal range of temperature is usually greater.

Tropical rainforests have four layers: Emergent Layer, Canopy Layer, Understory Layer and Forest Floor each with different plants and animals adapted for life in that particular area. 

Convectional type of rainfall mostly found in the equatorial zone. Two causes of this type of precipitation, (1) the intense heating of the surface so as to expand and raise the lower layer of the atmosphere and (2) abundant supply of moisture in the air to provide it with a high relative humidity. This type of rainfall mainly occurs in the summer month and in the warm part of the day. This type of precipitation is of very short duration and consist of heavy showers. Convectional rainfall is less effective for crop growth than the steady rain.   

Tropical rainforests or Natural forest have four layers:

Emergent Layer: These giant trees thrust above the dense canopy layer and have huge mushroom-shaped crowns.

Canopy Layer: The broad, irregular crowns of these trees form a tight, continuous canopy 60 to 90 feet above the ground.

Understory: Receiving only 2-15% of the sunlight that falls on the canopy, the understory is a dark place. It is relatively open and contains young trees and leafy herbaceous plants that tolerate low light. Many popular house plants come from this layer.

 Forest Floor: The forest floor receives less than 2% of the sunlight and consequently, little grows here except plants adapted to very low light. 

Amazon River is the largest river of the world. The basin made by this river is known as Amazon basin. It is the largest lowland in Latin America. It has a total area of 7 million square kilometers. Amazon basin is famous for dense forest cover. More than two-third of this basin is covered by immense forests. About half of the Earth's rain forests is found in Amazon basin.

The tropics are a region of the Earth surrounding the Equator. They are delimited in latitude by the Tropic of Cancer in the Northern Hemisphere at 23.5°) N and the Tropic of Capricorn in the Southern Hemisphere at 23.5°). The tropics are also referred to as the tropical zone and the torrid zone. 

The equatorial forest region experience very high temperatures throughout the year, the annual average temperature is being about 27 degrees celsius. The daily range of temperature is between 10 degrees Celsius to 25 degrees celsious. The rainfall is very heavy and distributed throughout the year. This region also received a sufficient amount of sunshine for all these the humidity level is very high in this region.

In equatorial region the temperature is high throughout the year, the annual average temperature is about 27 degree calcious. Rainfall is heavy and distributed throughout the year. The annual average rainfall is about 250cm. The constantly high temperature and all the year round rainfall helps to produce the most luxuriant evergreen vegetation in the region. So the forests of equatorial region are also known as evergreen. 

In forestry and ecology, understory comprises plant life growing beneath the forest canopy without penetrating it to any great extent, but above the forest floor. Only a small percentage of light penetrates the canopy so understory vegetation is generally shade tolerant.

What makes up most of the Canopy Layer is a tangled mix of vegetation including branches, vines and trees of different sizes. The trees rise to as much height as possible to gain maximum sunlight. 

Tropical diseases encompass all diseases that occur solely, or principally, in the tropics. In practice, the term is often taken to refer to infectious diseases that thrive in hot, humid conditions, such as malaria, leishmaniasis, schistosomiasis, onchocerciasis, lymphatic filariasis, Chagas disease, African trypanosomiasis, and dengue.

The equatorial region extends up to 10 degrees North and 10 degrees South in both the hemisphere. Here Climate is uniform, the high temperature throughout the year. The annual average temperature is about 27 degrees celsius. The daily range of temperature is between 10 degrees celsius. So the winter season is absent in the equatorial region.

Tropical rainforests have four layers: Emergent Layer, Canopy Layer, Understory, Forest Floor. 

The Kubu are southern Sumatra's indigenous inhabitants. As traditional hunters and gatherers, they have inhabited the lowland tropical forests of Jambi and South Sumatra provinces for centuries, where they survive by gathering an enormous variety of edible forest products, and hunting.

The African Pygmies (or Congo Pygmies) are a group of tribal ethnicities, traditionally subsisting in a forager and hunter-gatherer lifestyle, native to Central Africa, mostly the Congo Basin.

The Semang are the Negrito and Austric ethnic groups of the Malay Peninsula. They are found in Perak, Kedah and Pahang regions of Malaysia.

Shifting cultivation combines farming with forested habitats. It is also called swidden or slash and burn and is commonly found throughout the Amazon and other tropical regions worldwide. Shifting cultivation systems are designed to adapt to the soil and climatic characteristics like lower soil fertility, high precipitation, and fast leaching of nutrients.

Plantation farming involves the growing and processing of single cash crop for export to temperature lands. The plantation is organized on an efficient basis. The land is devoted to single crop and the entire production is exported to temperate land. During the time of colonization, the European introduced plantation agriculture in the equatorial regions. Areas of plantation farming, for the most part, lie near the sea because of ocean transport.

Tsetse, sometimes spelled also known as tik-tik flies, are large biting flies that inhabit much of tropical Africa. The bite leads to transmission of sleeping sickness and nagana.

Following are the cities on Equator.

1. Kinshasa, Democratic Republic of the Congo (4° 19′ 30″ S)

2. Bogota, Colombia (4° 35′ 53″ N)

3. Kaula lumpur, Malasia(3°8′ 51″N)

4. Singapore (1° 17′ 0″ N)

5. Medan, Indonesia (3° 35′ 0″ N)

6. Guayaquil, Ecuador (2° 11′ 0″ S)

7. Fortaleza, Brazil (3° 43′ 6″ S)

8. Cali, Colombia (3° 25′ 14″ N)

9. Nairobi, Kenya (1°17′0″S)

10. Quito, Ecuador (0° 15′ 0″ S)