Answer:
B: a population’s age-sex structure
Explanation:
A population pyramid is a way to visualize two variables: age and sex.
They are used by demographers, who study populations. A population pyramid is a graph that shows the distribution of ages across a population divided down the center between male and female members of the population. Expansive pyramids mean that the population does not increase much in total number and has many young people.
Hope this helps! Info from National Geographic, I would trust it if I were you!
To breath in the air, frog lowers the floor of the mouth. That causes throat to expand and nostrils to open. The air enters the mouth through nostrils and after that nostrils close. The floor of the mouth contracts to push the air into the lungs. To breath out the air, the floor of the mouth is lowered again and the air is pushed into the mouth. Nostrils open again and the air leaves the mouth.
Answer:
Empiece a utilizar Canva. ...
Seleccione una plantilla. ...
Personaliza tu diseño infográfico. ...
Perfecciona tu diseño con elementos. ...
Guardar y compartir.
Explanation:
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Answer:
Patent ductus arteriosus (PDA) is an extra blood vessel found in babies before birth and just after birth.
Explanation:
The ductus arteriosus is a normal blood vessel that connects two major arteries — the aorta and the pulmonary artery — that carry blood away from the heart.
The lungs are not used while a fetus is in the womb because the baby gets oxygen directly from the mother's placenta. The ductus arteriosus carries blood away from the lungs and sends it directly to the body. When a newborn breathes and begins to use the lungs, the ductus is no longer needed and usually closes by itself during the first 2 days after birth.
If the ductus doesn't close, the result is a patent (meaning "open") ductus arteriosus. The PDA lets oxygen-rich blood (blood high in oxygen) from the aorta mix with oxygen-poor blood (blood low in oxygen) in the pulmonary artery. As a result, too much blood flows into the lungs, which puts a strain on the heart and increases blood pressure in the pulmonary arteries.