There is a concern over the increase in harmful algal blooms in the seawaters of India. What could be the causative factors for this phenomenon?

1. Discharge of nutrients from the estuaries.
2. Run-off from the land during the monsoon.
3. Upwelling in the seas.

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The formation of the ozone hole in the Antarctic region has been a cause of concern. What could be the reason for the formation of this hole?

In the Union Budget 2011-12, a full exemption from basic customs duty was extended to the bio-based asphalt (bioasphalt). What is the importance of this material?

1. Unlike traditional asphalt, bio-asphalt is not based on fossil fuels.
2. Bioasphalt can be made from non-renewable resources.
3. Bioasphalt can be made from organic waste materials.
4. It is eco-friendly to use bioasphalt for surfacing of the roads.

Which of the statements given above are correct?

The “Red Data Book” published by the International Union for Conservation of Nature and Natural Resources (IUCN) contains lists of -

1. Endemic plant and animal species present in the biodiversity hotspots,
2. Threatened plant and animal species.
3. Protected sites for conservation of nature and natural resources in various countries.

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Salinization occurs when the irrigation water accumulated in the soil evaporates, leaving behind salts and minerals. What are the effects of salinization on the irrigated land?

The 2004 Tsunami made people realize that mangroves can serve as a reliable safety hedge against coastal calamities. How do mangroves function as a safety hedge?