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.
B. 245 million
from the end of Carboniferous Period to the beginning of the Triassic period
Answer:
2. meiosis I only
Explanation:
During the zygotene stage of prophase-I of meiosis-I, homologous chromosomes synapse and are paired up. These paired homologous chromosomes are called bivalents. These paired homologous chromosomes align themselves at the equatorial plate of the cell during metaphase-I. Therefore, when observed through a microscope, cells are shown lined up two by two. During meiosis-II and mitosis, individual chromosomes with two sister chromatids are aligned at the cell's equator in metaphase.
The layer of the sun is in three equally side the sun the moon and the galaxy
Answer:
The answer is either that he is a scientist or a chemist, but I think I’d go with scientist.
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