CO is not an element because CO is a Compound. Elements contain One capital and one lowercase letter. While Compounds contain two or more capital letters.
Answer:

Explanation:
To find the weight (W) of the pond contents first we need to use the following equation:
(1)
Where m the mass and g is the gravity
Also, we have that the mass is:
(2)
Where ρ is the density and V the volume
We cand calculate the volume as follows:
(3)
Where L is the length, w is the wide and d is the depth
By entering equation (2) and (3) into (1) we have:

Therefore, the weight of the pond is 6.65x10⁶ lbf.
I hope it helps you!
<span>The correct answer is 'freezing point depression'. Colligative properties depend on the concentration of molecules of a solute. Examples of other colligative properties are boiling point elevation or vapour pressure lowering. The salt causes ice on the side walk to melt because it lowers the freezing point. </span>
The answer is studying how people use time.
Hope this helps!
the correct answer would be the sun