Answer: Lung breathing: Mammals, birds, reptiles, and some amphibians.
Gill breathing: Fish and crabs.
Tracheal breathing: insects, centipedes, and spiders.
Skin respiration: Some amphibians, frogs.
The United States of America
<span>Develop theories based on their research is something that they always do in their work.
Sociologists will always tried to find the explanation of various social phenomenons. In order to find the answer, they need to formulate initial theories and conducted several researches/experiments in order to proof whether their theories are correct.</span>
The answer is D. Ethanol.
