some sort of defect in the bird's appearance

Anstobacco uses;  

Answer is b)eutrophication occurs when excess nutrients are present in aquatic ecosystems, resulting in the increased production of plant life and the subsequent decrease in the oxygen levels of the watereutrophication occurs when there are excess nutrients in a body of water. this results in plants having more food and reproducing  more, sometimes leading to more aquatic animal life as well. ultimately, this can reduce the oxygen level in the ecosystem. 

Airplanes usually fly in the lower part of the stratosphere - there is nearly no water vapor and it's very dry, so it to avoid big turbulences. it's about 8-10 kilometers above ground (depending on weather conditions, region etc.)

The best and most correct answer among the choices provided by the first question is the second choice " athens valued education above all else, while sparta valued physical fitness above all else"

on the other hand, the best and most correct answer among the choices provided by the second question is the fourth choice " kingdoms"

i hope my answer has come to your . god bless and have a nice day ahead!