The answer is A. Man-made
False
Nitrogen and sulfur dioxide are acidic oxides in nature. The burning of fossil fuels and other sources are responsible for addition of these oxides in the atmosphere of earth. These oxides mixed with water vapor causes acid rain. Being acidic in nature they will have low pH value. Therefore, greater the concentration of sulfur and nitrogen oxides, will lower the pH value of precipitation.
hope this helps:)sorry if it doesnt
Answer: B
Explanation:
Would be last, wouldn’t they? That would make the most sense to me.
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.
