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:
female, female
Explanation:
this is because sex-linked characters are normally borne in the X-chromosome
Answer:
Cell division is the mechanism by which DNA is passed from one generation of cells to the next and ultimately, from parent organisms to their offspring. During meiosis, the cells needed for sexual reproduction divide to produce new cells called gametes.
Answer: If a boa lays itself up next to you it is seeing if it can eat you without hurting itself...
