Problem: Aside from water, wood has three main components. Cellulose, a crystalline polymer derived from glucose, constitutes about 4143%. Next in abundance is hemicellulose, which is around 20% in deciduous trees but near 30% in conifers. It is mainly five-carbon sugars that are linked in an irregular manner, in contrast to the cellulose. Lignin is the third component at around 27% in coniferous wood vs. 23% in deciduous trees. Lignin confers the hydrophobic properties reflecting the fact that it is based on aromatic rings. These three components are interwoven, and direct covalent linkages exist between the lignin and the hemicellulose. A major focus of the paper industry is the separation of the lignin from the cellulose, from which paper is made.
Which of the three main components of wood is used to manufacture paper?
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Answer: cellulose

Problem: The origins of the people of Tuvalu are addressed in the theories regarding migration into the Pacific that began about 3000 years ago. During pre-European-contact times there was frequent canoe voyaging between the nearer islands including Samoa and Tonga. Eight of the nine islands of Tuvalu were inhabited; thus the name, Tuvalu, means "eight standing together" in Tuvaluan (compare to *walo meaning "eight" in Proto-Austronesian). Possible evidence of fire in the Caves of Nanumanga may indicate human occupation for thousands of years.
How many islands are in the Tuvalu group?
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Answer: nine islands

Problem: Cooperative breeding in birds typically occurs when offspring, usually males, delay dispersal from their natal group in order to remain with the family to help rear younger kin. Female offspring rarely stay at home, dispersing over distances that allow them to breed independently, or to join unrelated groups. In general, inbreeding is avoided because it leads to a reduction in progeny fitness (inbreeding depression) due largely to the homozygous expression of deleterious recessive alleles. Cross-fertilization between unrelated individuals ordinarily leads to the masking of deleterious recessive alleles in progeny.
Why is inbreeding avoided?
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Answer:
because it leads to a reduction in progeny fitness