Answer:a weak acid and a weak base
Explanation:
"One possibility is that the battle between the virus and your immune system can take as long as two weeks.
It could be the immune system holds the virus at bay,” said Tompkins.
Or, your immune system has to work so hard that after two weeks it’s inflamed and that’s what makes you feel bad.
The base units of length and volume are linked in the metric system. By definition, a liter<span> is equal to the volume of a cube exactly 10 </span>cm<span> tall, 10 </span>cm<span> long, and 10 </span>cm<span> wide. Because the volume of this cube is 1000 cubic </span>centimeters<span> and a </span>liter<span> contains 1000 milliliters, 1 milliliter is equivalent to 1 cubic centimeter.</span>
90% of energy is lost. only 10% is left.
therefore the answer is B. 90%
Option (a) is correct.
A reducing agent is the one which loses electrons to other substance and an oxidizing agent is one which accepts electrons.
Here, In

, Cr has oxidation number 6+ in the L.H.S of the equation, but on R.H.S its oxidation number is 0 i.e. it Cr has gained electrons such that total charge is 0.
And the oxidation state of Al in the left-hand side of equation is 0 and in right-hand side, it is +6.i.e. it has donated its electrons to Cr.
Hence, Cr is the oxidizing agent and Al is the reducing agent.