1)How long did it take for the third of population to double?How long did it take for the population to double a third time? 2) 51 years
___________ A third time? It took 75 years for the population to double a second time and it took 51 years to double a third time. It will reach 8 billion at about 2024. 4.
Answer:
Substance B is a group of hydroxide ions.
Explanation:
If the inner lining of the air sacs neither thin nor highly vascularized, then it can be inferred that AIR SACS ARE CANNOT BE THE SITES OF GASEOUS EXCHANGE BETWEEN AIR AND BLOOD. Air sacs are generally lined with mucus and surrounded with blood capillaries.
In case of birds, air sacs play an important role in respiratory system.
