All eukaryotic cells have membrane covered compartment called organelles. They include the nucleus, the Golgi, mitochondria, endoplasmic reticulum and many others. So the answer is- organelles. ;)
It is a substance.
Having chemicals or bad things in it.
Why didn't you go to dictionary.com?
Answer:
Tectonic movement forced certain segments of Earth's crust downward and other segments upward in jagged chunks.
Explanation:
The number of H+ ions moving down the channel.
So id say the answer is C.