The order of flow of oxygen within the human body may be described simply. Oxygen first is inhaled through the nasal cavity and then passes through the trachea, through the bronchi and into the lungs. In the lungs, the oxygen is passed into the blood stream through the alveoli and then is carried to the heart. The heart pumps this oxygenated blood throughout the body, primarily to organs and muscle cells, where it is consumed in respiration and is converted to carbon dioxide and excreted.
I think it may be conservation.
Answer:
it's 2
I don't know how to explain but yeah its 2
I'd say the answer to this one is B, skunks and toads have a predator-prey relationship. Good Luck!
A parasite invades the species and causes its population to decline because a biotic factor is a living factor that affects a species
