An element is a chemical substance that cannot be broken down into simpler components in a chemical reaction or by any chemical means, and is made up of atoms that all have the same number of protons. Pure chlorine is an example of an element because it contains only one kind of an atom. Chlorine is a toxic, green, gaseous chemical element. Chlorine is a halogen, has an atomic number of 17, symbol Cl and is found in group 17 in the periodic table. Chlorine is highly reactive and a strong oxidizing and disinfecting agent.
1 light year is 63,270 AU, which means that the distance to the nearest star is 272,061 AU. We took the radius of the solar system to be 39.5 AU, which means it has a diameter of 79 AU.
Pneumatization/honeycomb structure in bones allows for the birds to weigh less and be buoyant
Birds have lightweight feathers on the wings hence allowing for a higher lift to weight ratio.
Birds take in very little water in their bodies hence reducing on the carried weight. This is why birds excrete their waste as uric acid that requires less water to eliminate compared to ammonia
Instead of boned jaws, birds have beaks made of keratin which is lightweight
The breastbone of birds is enlarged allowing for the attachment of muscles involved in flight