You're correct because when birds hit their max altitude it's harder to breathe and to minimize the time of there flight they store immense amounts of oxygen in their lungs.
The cause of the change in insect characteristics occurred when a few survivors of the 1st spray became resistant to the insecticide. When they had offspring, those insect babies are born with the trait that made them resistant to insecticide. This occurs when the parents pass on the trait to their offspring. The end result is that the insecticide is less effective and more insects survive.
Cell, Tissue, Organ, Organ System
(Hope this Helps)
<span>Stem cells are found in multicellular organism,they are undifferentiated in nature and can form other special cells or could divide in further stem cells by mitosis.The person with brain or spinal cord injury would be interested cause these cells could be used in future to cure the problem.Human embryonic stem cell (HESC) research is ethically and politically controversial because it involves the destruction of human embryos.The resource used was paper by B Lo named 'Ethical Issues in Stem Cell Research'.And according to me research in this field is important for development of mankind</span>