Flight has been an important innovation for animals and has led to adaptive radiations in both birds and insects. For birds, what additional fitness benefits have been gained through adaptations for flight? A. Reductions in reproductive organs has led to the production of eggs with a larger allantois, increasing nutrients for their offspring. B. Birds rely on metabolic heat to stay warm and feathers help birds regulate their body temperature. C. The lack of teeth means that birds have become dietary specialists, optimized for eating exclusively grains (land-dwellers) or fish (shore-dweller). D. The relative metabolic rate (per kg) is lower in lighter vertebrates, which means that birds need loss food than other reptiles of a similar size.

answer: carbon 14 can only be used to determine the age of the organisms that were once living, and igneous rocks are non living.

explanation:

carbon 14 dating is used to determine the age of the sample by estimating the amount of carbon 14 present in the sample and then comparing it with a reference standard.carbon 14 is a isotope of carbon which is radioactive and unstable. carbon 14 is assimilated by all plants and animals throughout their life from carbon dioxide. however, one the organisms die they stop this assimilation and the carbon 14 content starts to decrease.by knowing how much of carbon 14 is left in an organism after his death, one can estimate the age of the organism. the materials whose age can be estimated by carbon 14 method are the organic compounds. however, some inorganic compounds such as aragonite   shell can also be dated.however, if we consider the igneous rocks it is a non living component which never accumulated carbon 14 in it and thus, we cannot use carbon 14 dating method to estimate its age.

It would be the equator.

The correct answer is:       [c]:   "organisms that are sensitive to changes in temperature would die. "