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.

d.) circle motion requires a force to give it a centripetal acceleration.

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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