Chest Radiology > Pathology > Atelectasis > General. Atelectasis is collapse or incomplete expansion of the lung or part of the lung. This is one of the most common findings on a chest x-ray. It is most often caused by an endobronchial lesion, such as mucus plug or tumor.
A Labradoodle, a crossbreed between a poodle and a retriever. A crossbreed or crossbred usually refers to an organism with purebred parents of two different breeds, varieties, or populations.
Best Answer: Crossing-over is another name for recombination or physical exchange of equal pieces of adjacent non-sister chromatids. When crossing-over occurs chromatids break and may be reattached to a different homologous chromosome.