4. What is the salinity of seawater?
1.5 percent
3.5 percent
10 percent
5.5 percent

I think the answer is 3.5%

Explanation:

35 parts per thousand of seawater contains salt therefore your answer is 3.5

photosynthesis makes the glucose that is used in cellular respiration to make atp. the glucose is then turned back into carbon dioxide, which is used in photosynthesis. while water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water.