The question asks about the interaction between silt-laden fresh water and salt water. This phenomenon is common in estuaries where rivers meet the sea. The key concept here is the effect of electrolytes (salts) on suspended particles like silt.
Correct Option: D) Precipitation of suspended matter occurs. This option accurately describes the process of flocculation and subsequent settling of silt particles when they encounter the electrolytes in salt water.
The question asks about the relationship between soil erosion and rainfall based on an implied passage (though the passage itself is not provided, common knowledge about environmental science is expected). We need to evaluate each option to find the most accurate connection.
B) Preventing soil erosion also conserves water. When soil is healthy and not eroded, it acts like a sponge, absorbing and retaining rainfall. This process allows water to percolate into the ground, replenishing groundwater and making it available for plants and other uses. Conversely, eroded soil has reduced infiltration capacity, leading to increased surface runoff and less water conservation.
The question asks for the primary reason for controlling water flow based on an assumed passage. Without the passage, we must infer the most common and significant environmental reason for controlling water flow, especially in the context of resource management and environmental protection.
Correct Option: C) To prevent soil erosion and conserve resources
This option directly addresses a critical environmental problem caused by uncontrolled water flow and highlights the conservation aspect, which is a primary goal of water management.
The question asks what the passage implies about the future of agriculture in India. To answer this, we need to carefully read the passage (which is not provided in the prompt but is implied by the question and options) and identify key statements or themes related to Indian agriculture. Since the correct option is given as A, we will assume the passage highlights the dependence on seasonal rainfall.
Correct Option: A) It is heavily dependent on seasonal rainfall. This option is consistently true for Indian agriculture, where the monsoon plays a crucial role in crop production. Any passage discussing the challenges or future of Indian agriculture would likely highlight this dependency, especially in the context of climate change or irrigation needs.
The question asks for the primary reason behind emphasizing the development of internal waterways in India. We need to evaluate each option based on the known advantages of inland water transport.
Correct Option: C) They are cheaper than rail and road transport.
Internal waterways offer a highly cost-effective and fuel-efficient mode of transport, particularly for bulk cargo. The operational costs and environmental footprint are generally lower compared to road and rail transport, making their development crucial for economic efficiency and reducing logistics costs in India.
The question asks to identify one of the most urgent needs in India based on an unprovided passage. Since the passage is not given, we must infer the likely urgent need from the given options, assuming the passage discusses environmental or developmental challenges common in India.
D) Systematic afforestation — This is a critical need in India to combat deforestation, soil erosion, climate change, and loss of biodiversity. Many reports and studies emphasize the urgent need for increasing forest cover for ecological balance and sustainable development. Given the severe environmental challenges India faces, systematic afforestation is indeed one of the most urgent needs.