Geography

Step 1: Understanding the Concept:
A population pyramid graphically represents the age and sex distribution of a population. The shape of the pyramid provides insights into birth rates, death rates, and life expectancy.
- The base of the pyramid represents the youngest age groups (births). A wide base indicates a high birth rate, while a narrow base indicates a low birth rate.
- The top of the pyramid represents the oldest age groups. A tapered top is normal, but a rapidly tapering top indicates a high death rate and low life expectancy. A less tapered top (more people in older age groups) suggests a low death rate and high life expectancy.
Step 2: Detailed Explanation:
The question describes a pyramid with a narrow base and a tapered top.
- Narrow base: This directly indicates a low birth rate. There are fewer young people.
- Tapered top: While all pyramids taper, in the context of a narrow base, this shape (often called a constrictive or urn-shaped pyramid) is characteristic of developed countries with an aging population. This implies a low death rate and longer life expectancy, allowing a significant portion of the population to reach old age before the pyramid tapers.
Therefore, the combination is a low birth rate and a low death rate.
Step 3: Final Answer:
A population pyramid with a narrow base and a tapered top is characteristic of a population with a low birth rate and a low death rate.

Step 1: Understanding the Concept:
The heat content (calorific value) of coal is directly related to its rank or stage of formation (coalification). The longer the coal has been subjected to heat and pressure, the higher its carbon content and heat content. The question asks for the order from lowest to highest heat content.
Step 2: Detailed Explanation:
The ranks of coal from lowest to highest are:
1. (A) Peat: This is the precursor to coal. It has low carbon content, high moisture, and the lowest heat content.
2. (B) Lignite: Also known as brown coal, this is the lowest rank of coal. It has a higher heat content than peat.
3. (E) Sub-bituminous: This is the next rank up from lignite, with lower moisture and higher carbon content.
4. (D) Bituminous: This is a dense, black coal with a high heat content. It is the most abundant type of coal.
5. (C) Anthracite: This is the highest rank of coal. It has the highest carbon content, the lowest moisture, and the highest heat content.
Step 3: Final Answer:
The correct increasing order of heat content is Peat

Step 1: Understanding the Concept:
The question asks to identify the layers of the Earth's atmosphere where the temperature profile shows a decrease in temperature with an increase in altitude. This is known as a negative lapse rate.
Step 2: Detailed Explanation:
Let's examine the temperature profile of each layer, starting from the ground up:
- (A) Troposphere (0-12 km): This is the lowest layer where we live and where most weather occurs. The temperature decreases with altitude because the air is heated from the ground up by terrestrial radiation.
- (D) Stratosphere (12-50 km): Temperature increases with altitude in this layer. This is due to the absorption of ultraviolet (UV) radiation by the ozone layer.
- (B) Mesosphere (50-80 km): Above the stratosphere, the temperature once again decreases with altitude. This is the coldest layer of the atmosphere.
- (C) Thermosphere (80+ km): Temperature increases dramatically with altitude due to the absorption of high-energy solar radiation by the sparse gas molecules.
Step 3: Final Answer:
Temperature decreases with increasing height in the Troposphere (A) and the Mesosphere (B). Therefore, the correct option is (A) and (B) only.

Step 1: Understanding the Concept:
The question asks to identify the ideal soil type for most plant growth. The suitability of soil depends on its texture, which is a mix of sand, silt, and clay particles. This mix affects water retention, drainage, and aeration.
Step 2: Detailed Explanation:
- Clayey silt / Silty Clay: These soils have a high percentage of clay and silt. They can hold a lot of water but often have poor drainage and aeration, which can suffocate plant roots.
- Sandy loam: This soil has a higher percentage of sand. It offers good drainage but may not retain enough water or nutrients for many plants.
- Loamy soil: This is considered the ideal soil for gardening and agriculture. It contains a balanced mixture of sand, silt, and clay, along with organic matter (humus). This balance provides good drainage, adequate water and nutrient retention, and sufficient air space for roots to breathe.
Step 3: Final Answer:
Loamy soil is the most suitable for plant growth due to its balanced properties.

Step 1: Understanding the Concept:
The question asks to identify which of the given Indian states has a population where Christians form the majority religion.
Step 2: Detailed Explanation:
Let's look at the religious demographics of the states listed (based on the 2011 Census):
- Meghalaya: Christians constitute approximately 74.6% of the population, making it a Christian-majority state.
- Tripura: The majority religion is Hinduism (around 83%), with Christians being a small minority.
- Kerala: While Kerala has a significant Christian population (around 18%), they are a minority. Hinduism is the majority religion (around 55%), followed by Islam (around 26%).
- Sikkim: The majority religion is Hinduism, followed by Buddhism. Christians are a minority.
Other Christian-majority states in India include Nagaland and Mizoram.
Step 3: Final Answer:
Among the given options, Meghalaya is a Christian-majority state.