Answer:
The combination of the Suns revolution and the fixed angle of the Earths axis results in seasonal changes
Answer:
The BOD5 for this sample is 5 mg/L
Explanation:
The BOD5 takes into consideration the difference between the initial DO and the final DO divided by the fraction of the sample tested in a 300 mL BOD flask. The problem states that the sample was directly placed in a BOD bottle so we assume that the volume used was 300 mL of the water sample. The fraction of water is 1 (300/300).

BOD5 = (10-5)/1
BOD 5 = 5 mg/L
Answer:
The elevation changes from 635 to 600 at the picnic area.
Explanation:
In the picnic area which is close to point 4 on the map, the elevation changes from 635 to 600. We see that the site chosen for the picnic has a very gentle elevation and would be easily taken as a flat plain surrounded by hills.
The contours here are far apart and it implies a flat area with gentle slope. The only creek here is the equation creek. The area is below 635.