Answer:D
Explanation: The pulmonary air sacs of birds only permit a unidirectional flow of air through the lungs. Unidirectional flow means that air is inhale and exhale through one trachea alternatively. This means the bird lungs only receive largely fresh air which has a high oxygen content during inhalation and do not receive fresh during exhalation. While air flow bidirectional in mammals.
Answer:
with each heartbeat,the heart pumps blood throughout our bodies,carrying oxygen to every cell,after delivering oxygen the blood returns to the heart the heart then sends the blood to the lungs to pick up more oxygen.
F ( 18 ) = 1,50 * 18 + 12.50 = 27.00 + 12.50 = $39.50,
x - number of movies.
Answer: D ) $39.50; this is the amount Kelsey pays for 18 movies in 1 month
Whats the experiment? there's no experiment here
Biotic would mean living so fish and sea plants
