The transition directly from a solid to a gas
First eliminate choices C and D since they both mention that fact 1 is crossing over ( which is also referred to as genetic recombination) . So you're left with A and B and the correct answer is B .
Water is important to living think because they need it to live
I believe the answer would be Letter
B. Psychology
Alveolar walls are thin to enable the quick passage of oxygen in and out of the lungs. The lungs works hand-in-hand with the heart and also is responsible in converting blood that's de-oxygenated into an oxygenated blood that is usable by the organ systems of the body. The alveolar walls are also designed to have thin membranes so that it can expand and constrict quickly allowing us to breather properly.
