Answer:
a) No molecules of hydrogen
b) four molecules of ammonia
c) four left molecules of nitrogen.
Explanation:
The balanced reaction between nitrogen and hydrogen molecules to give ammonia molecules is:

Thus one molecule of nitrogen will react with three molecules of hydrogen to give two molecules of ammonia.
We have six molecules of each nitrogen and hydrogen in the closed container and they undergo complete reaction it means the limiting reagent is hydrogen. For six molecules of nitrogen, eighteen molecules of hydrogen will be required.
So six molecules of hydrogen will react with two molecules of nitrogen to give four molecules of ammonia.
The product mixture will have
a) No molecules of hydrogen
b) four molecules of ammonia
c) four left molecules of nitrogen.
The biggest reason is radioactive wastes. Nuclear power generated radioactive wastes like Uranimum, plutonium and amercium that inhibits gene expression and causes cancer to the environment. Nuclear plants use to release these wastes into the oceans, and it causes fishes to exhibit gender change, 3 eyes, 2 tails etc. The impact on human shows signs of serious blood, liver and lung cancers.
There are currently no way to get rid of these wastes as they take hundred thousands of years to decompose.
Another reason is they cause a small amount of green gas emission. Releases CO2 to the sky. They exhibit radioactive gas emission as well (causes cancer) .
You didn’t post the whole question :/