The first most obvious thing to note is when naming transitional metals, you have to state its charge with roman numerals (except for 1 if I remember correctly). For example, Iron (lll), iron has a charge of 3.
The given question is incomplete. The image present in the question for Reaction A is attached below along with the answer.
Explanation:
Pyruvate molecule reacts with Coenzyme A in the presence of oxygen and it results in the formation of acetyl Coenzyme A and carbon dioxide.
The enzyme pyruvae dehydrogenase helps in catalyzing this reaction. As in this biochemical reaction 
gets converted into NADH.
This reaction is shown in the image attached below.
Answer:
Explanation:
What occurred then is as a result of nuclear fission. This occurs as the Uranium-235 split into two smaller nuclei while releasing high energy neutrons. These neutrons bombard existing U-235 in the atmosphere and this reaction continue in a spontaneous manner until a chain reaction is formed of U-235, whose fall out fills the environment. This process was what led to people been exposed to high intensity radiation in the days and months after the atomic bomb was dropped.
