Identify the factors contributing to the high oxygen content in the surface layer of water.

1. High rates of respiration by aquatic organisms.
2. Maximum production of oxygen through photosynthesis.
3. Limited contact with the atmosphere, reducing oxygen diffusion.
4. Presence of decomposers actively consuming oxygen.

Why is the overturn process important for lakes that undergo stratification?

1. It prevents the formation of ice cover.
2. It ensures thorough mixing of oxygen, phytoplankton, and nutrients.
3. It leads to the accumulation of sediments at the bottom.
4. It only affects the temperature of the surface water.

What causes the sinking of water during the autumn (fall) overturn?

1. The surface water gets warmer and sinks.
2. The surface water cools down to 4°C, becoming denser and sinking.
3. The density of water decreases as it cools.
4. Increased solar radiation causes the water to become heavier.

Which of the following statements about spring overturn is correct?

1. It occurs when the surface water cools down to 4°C.
2. Increased solar radiation melts the ice, and water at 4°C sinks.
3. It is primarily driven by the cooling of air temperatures.
4. The process involves warm surface water sinking to the bottom.

What are the two main seasons when lake water overturn occurs?

1. Spring and Autumn (Fall)
2. Summer and Winter
3. Late Winter and Early Spring
4. Late Summer and Early Winter

What is the primary process described in the provided text regarding lake water circulation?

1. Lake water circulation occurs annually in summer and winter.
2. The process of overturn involves the mixing of lake water layers.
3. Overturn primarily helps in distributing dissolved gases and nutrients within the lake.
4. Overturn is a process exclusive to tropical lakes.

Match the following ecosystems correctly:

Lentic	Freshwater meets saltwater
Lotic	Still water
Wetlands	Marshes and swamps
Estuaries	Flowing water

Semi-arid deserts are best described as:

Which desert ecosystem is characterized by being near the ocean and having fog as a water source?

The Gobi Desert in Asia is an example of which type?

Which of the following is a characteristic feature of hot and dry deserts?

The mixing of freshwater and saltwater takes place in which ecosystem?

Coral reefs are found in which type of ecosystem?

Which aquatic ecosystem includes marshes, swamps, and bogs?

The Amazon River is classified under which type of freshwater ecosystem?

Which of the following is an example of a lentic ecosystem?

Which of the following is an example of ex-situ conservation?

Protecting biodiversity within its natural habitat is known as:

Which of the following is not listed as a threat to biodiversity in the given content?

How many biodiversity hotspots are identified globally, and how many are present in India?

Which condition is necessary for an area to be declared a biodiversity hotspot?

The distribution of biodiversity is:

Which level of biodiversity refers to variation within species that helps in adaptation?

The term Biodiversity was first coined by:

Freshwater ecosystems include which of the following?

Which of the following is not a natural terrestrial ecosystem?

Which one of the following is not correctly matched?

Which of the following nutrient cycles lacks a major gaseous component?

Nitrogen-fixing bacteria like Rhizobium are associated primarily with which part of the nitrogen cycle?

Which of the following correctly describes the direction of energy flow in an ecosystem?

Lindeman’s law in ecosystem energy flow is also known as:

Net Primary Productivity (NPP) can be expressed as:

Consumers in an ecosystem include all of the following except:

Which among the following represents the “producers” in an ecosystem?

Which of the following is not an abiotic factor in an ecosystem?

The term ecosystem was first coined in 1935 by:

Which statement correctly describes the Metalimnion?

1. The Metalimnion is the uppermost layer, characterized by warm, circulating water.
2. It lies below the Hypolimnion, acting as the transition zone to the surface water.
3. The Metalimnion forms the intermediate layer of the lake, marked by a steep fall in temperature.
4. This layer is known for its high oxygen content due to constant mixing with the atmosphere.

Regarding the Epilimnion layer, which of the following statements is correct?

1. It is the bottom-most layer of the lake, characterized by cold, nutrient-poor water.
2. The Epilimnion is the upper layer of the lake, containing freely circulating warm water.
3. It is well-aerated primarily due to decomposition processes occurring at the bottom.
4. The Epilimnion is well-lit but typically poor in dissolved oxygen.

Consider the characteristics of the Hypolimnion layer in a stratified lake. Which statement is accurate?

1. The Hypolimnion is the upper, circulating layer rich in oxygen and nutrients.
2. The Hypolimnion is the bottom layer characterized by cold temperatures and low oxygen levels.
3. Decomposition processes in the Hypolimnion consume nutrients and produce oxygen.
4. The temperature in the Hypolimnion experiences a steep fall with increasing depth.

What are the key factors contributing to pronounced thermal stratification in lakes during summer?

1. Increased solar intensity during summer heats the surface layer significantly, while lower layers remain cooler.
2. The rapid mixing of water layers by strong winds prevents the formation of distinct temperature gradients.
3. The thermally stratified layers offer resistance to mixing by wind, helping to maintain the temperature differences.
4. A decrease in solar radiation during summer leads to the formation of thermal gradients.

Which of the following statements accurately describe summer stratification in temperate lakes?

1. Summer stratification is a phenomenon where lakes develop distinct temperature layers.
2. In temperate regions, thermal stratification is rare and only occurs in very deep lakes.
3. The top meter of the water surface absorbs approximately 90% of solar radiation, leading to its significant heating.
4. Tropical lakes exhibit pronounced summer stratification due to slow mixing rates.

What are the primary reasons for pronounced thermal stratification in lakes during the summer season?

1. Decreased solar intensity leads to greater heating of the surface layer.
2. The surface layer of the water absorbs a significant portion of the solar radiation, leading to increased heating.
3. The lower layers remain comparatively cool due to receiving progressively less solar radiation.
4. The thermally stratified layers offer enhanced mixing by wind.

Identify the correct statements regarding the thermal stratification layers in a lake during summer.

1. The epilimnion is the upper layer, characterized by warm, circulating water, rich in nutrients, and supporting phytoplankton growth.
2. The metalimnion is the intermediate layer where water temperature decreases sharply with increasing depth.
3. The hypolimnion is the bottom layer, which is cold, non-circulating, and typically low in oxygen but rich in nutrients.
4. Phytoplankton predominantly grow in the hypolimnion due to high nutrient availability.

Which of the following statements accurately describe summer stratification in temperate lakes?

1. Summer stratification is pronounced in temperate lakes due to the rapid mixing of water layers.
2. Temperate lakes retain well-defined temperature layers that do not mix rapidly during summer.
3. Tropical lakes exhibit pronounced summer stratification because their layers mix slowly.
4. Summer stratification is rare in deep tropical lakes.

Which of the following statements about dissolved oxygen in lake ecosystems is correct?

1. Dissolved oxygen is generally higher in stagnant lake waters compared to flowing lotic systems.
2. The oxygen content in lakes typically decreases with depth.
3. Only the surface layer of a lake interacts with atmospheric oxygen.
4. Decomposition of organic matter does not affect dissolved oxygen levels.

Regarding the factors influencing zonation in lake ecosystems, which statement is correct?

1. Horizontal zonation in lakes is solely determined by the direct influence of sunlight and temperature.
2. Vertical zonation is a direct result of temperature, sunlight, and oxygen gradients.
3. The distribution of lake organisms does not play a role in horizontal zonation.
4. Dissolved oxygen levels are uniform at all depths in a lake.

Which of the following statements accurately describe the characteristics of lake ecosystems?

1. Lake ecosystems, unlike lotic ecosystems, are characterized by static water bodies.
2. Light penetration in lakes is consistently uniform throughout the water column.
3. Dissolved oxygen levels in lakes are typically higher than in lotic systems due to greater surface area contact with air.
4. Vertical zonation in lakes is primarily influenced by variations in temperature, sunlight, and dissolved oxygen.

Consider the definition of wetlands. Which statement is incorrect?

1. Wetlands can be saturated with water periodically.
2. Wetlands can be artificially created.
3. Wetlands are exclusively land areas completely submerged in water permanently.
4. The water covering wetlands can be up to a depth of 6 meters.

What type of water is typically found in Coastal wetlands?

1. Only freshwater.
2. Saline or brackish water.
3. Purely desalinated water.
4. Water with varying salinity levels.

Which of the following are examples of Inland wetlands?

1. Mangrove swamps
2. Bogs
3. Mangrove Forests
4. Swamps