Agraph of coal reserves in the united states versus time slopes downward this indicates that coal production could have
decreased
increased
fluctuated
stayed the same

Option A.

Explanation:

It is given that a graph of coal reserves in the united states versus time slopes downward.

It means, in the graph x-axis represents the time and y-axis represents the coal reserves.

Negative slope represents the negative relation between coal reserves and time. It means coal reserves will decrease if time increases.

In other words, the downward slope indicates that coal production could have decreased.

Therefore, the correct option is A.

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.