Answer:
B) The normal pH of blood is 6.8 to 7.0.
Explanation:
The blood pH under normal health conditions is between 7.35 and 7.45. Below this range, blood pH is considered more acidic than normal, and it may indicate that the body is eliminating a lower amount of 
than normal, or that there is a decrease in the concentration of 
or accumulation of acid in the blood due to poisoning or disease.
The answer is a “rises because it is less dense than cold air”
15. B.
16. G. schlerenchyma cells
17. D. ATP
The answer is microscopic life appeared on Earth before flowering plants. This is because according to the label on the second box, microscopic life appeared 4.0 to 3.5 billion years ago, and this is way before the date 250 to 120 millions years ago indicated on the label on the sixth box the flowering plants appeared on Earth.
