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:
stomach
Explanation:
it is obious cause even 6 standard children know it
Yes, stimulating it with electrodes can potentially help improve mood and alleviate symptoms in those who suffer from treatment-resistant depression, among other ailments.
Yes, when the egg and a sperm cell meet fertilization has taken place
Answer:
It was a prank
Explanation:
everyone decided to prank percy and act like mrs dodds didnt exist