Answer:
B) FADH2 -- FMN of Complex I -- Fe-S of Complex II -- Q -- Fe-S of Complex III -- Cyt c -- Cyt a of Complex IV -- O2
Explanation:
FADH2 and NADH give their high energy electrons to the terminal electron acceptor molecular oxygen via an electron transport chain. As the electrons move through electron carriers of the electron transport chain, they lose their free energy. Part of the free energy of the electrons is used to pump the protons from the matrix into the intermembrane space. Therefore, part of the energy of electrons is temporarily stored in the form of a proton concentration gradient.
NADH gives its electrons to FMN of complex I while FADH2 gives its electrons to the Fe-S center of complex II. Both the complexes are oxidized by coenzyme (Q) which in turn reduces Fe-S centers of complex III. Cyt c of complex IV obtains electrons from complex III and passes them to CuA center, to heme "a" to heme "a3-CuB center" and finally to the molecular oxygen.
So, the compounds arranged with respect to the energy content of electrons in descending order are as follows: FADH2 -- FMN of Complex I -- Fe-S of Complex II -- Q -- Fe-S of Complex III -- Cyt c -- Cyt a of Complex IV -- O2.
A pure substance is any substance on its own. For example, sand is impure for containing lots of different substances. However, diamonds are mostly pure for only containing one type of substance.
Whether a substance is pure or not doesn't relate to a substance's molecular structure, but different molecules in a substance. Water by itself is only H2O, therefore it still pure.
Water is not an element but a compound for containing different elements, however it still pure.
The sentences that make sense are "Volatile liquids are flammable" and "Liquids burn easily."
