Which structures are most similar in birds and mammals based on their functions? air sacs in birds and rib cages in mammals air sacs in birds and mammary glands in mammals gizzards in birds and teeth in mammals crops in birds and teeth in mammals?

The right option is; Air sacs in birds and rib cages in mammals

Birds have relatively small lungs plus nine air sacs that play an important role in respiration. The air sacs allow a unidirectional flow of air through the bird lungs. In mammals, the ribs are the long curved bones that form the rib cage. The rib cage surrounds the chest and allows the lungs to expand and thus facilitate breathing by expanding the chest cavity.

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.