For the measurement/estimation of which of the following are satellite images/remote sensing data used? I. Chlorophyll content in the vegetation of a specific location II. Greenhouse gas emissions from rice paddies of a specific location III. Land surface temperatures of a specific location Select the correct answer using the code given below.

All three are measured through remote sensing, so the answer is D. The core concept is that satellite sensors record reflected and emitted radiation, and specific bands or indices convert that into a surface or atmospheric property.

• Statement I (chlorophyll content): Chlorophyll absorbs strongly in the red band and reflects strongly in the near-infrared. Indices such as NDVI, and red-edge based chlorophyll indices from multispectral sensors, are standard tools for crop and vegetation health.
• Statement II (greenhouse gases from rice paddies): Methane from flooded paddies is estimated using column concentration retrievals from sensors such as GOSAT and Sentinel-5P TROPOMI, combined with ground data and models.
• Statement III (land surface temperature): Thermal infrared bands on Landsat and MODIS measure emitted radiance, which is converted into land surface temperature.

Mains connection: GS-III topics on agriculture, climate change and disaster monitoring rely on exactly these datasets, and ISRO and NRSC programmes are the Indian side of this work.

Trap: Aspirants assume satellites cannot measure gases and eliminate II. Column gas retrievals are remote sensing products, even though ground validation is still needed.