instruction:
In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
question:
What is the area of expertise of scientists who want to measure radiance from vegetation canopies?, Context: Oxygen presents two spectrophotometric absorption bands peaking at the wavelengths 687 and 760 nm. Some remote sensing scientists have proposed using the measurement of the radiance coming from vegetation canopies in those bands to characterize plant health status from a satellite platform. This approach exploits the fact that in those bands it is possible to discriminate the vegetation's reflectance from its fluorescence, which is much weaker. The measurement is technically difficult owing to the low signal-to-noise ratio and the physical structure of vegetation; but it has been proposed as a possible method of monitoring the carbon cycle from satellites on a global scale.
answer:
remote sensing


question:
From what era, once thought devoid of animal life, was evidence of grazer populations discovered?, Context: Some paleontologists suggest that animals appeared much earlier than the Cambrian explosion, possibly as early as 1 billion years ago. Trace fossils such as tracks and burrows found in the Tonian period indicate the presence of triploblastic worms, like metazoans, roughly as large (about 5 mm wide) and complex as earthworms. During the beginning of the Tonian period around 1 billion years ago, there was a decrease in Stromatolite diversity, which may indicate the appearance of grazing animals, since stromatolite diversity increased when grazing animals went extinct at the End Permian and End Ordovician extinction events, and decreased shortly after the grazer populations recovered. However the discovery that tracks very similar to these early trace fossils are produced today by the giant single-celled protist Gromia sphaerica casts doubt on their interpretation as evidence of early animal evolution.
answer:
the Tonian period


question:
Who was responsible for making changes in the bels at the abbey?, Context: The bells at the abbey were overhauled in 1971. The ring is now made up of ten bells, hung for change ringing, cast in 1971, by the Whitechapel Bell Foundry, tuned to the notes: F#, E, D, C#, B, A, G, F#, E and D. The Tenor bell in D (588.5 Hz) has a weight of 30 cwt, 1 qtr, 15 lb (3403 lb or 1544 kg).
answer:

the Whitechapel Bell Foundry