Thinking about the uses of radioactive isotopes, which statement is true?

Question

A. The iodine isotope, I-27, is used to diagnose thyroid disorders.
B. Radiation may be detected because it ionizes the atoms it affects.
C. It’s clearly understood that irradiating food kills bacteria and contaminates
the food.
D. Radioactive isotopes used in medical diagnoses have long lives and are quickly
absorbed by the body.
(A?)

Regarding nuclear reactions that release a great deal of energy,
which statement is true?
A. In a fission chain reaction, a uranium nucleus struck by a
high-energy neutron emits two neutrons.
B. Nuclear fission releases more energy per unit mass than
does a fusion reaction.
C. Nuclear reactors produce dangerous levels of air pollution.
D. A fusion reaction proceeds through the joining of two
isotopes of hydrogen.
(D?)

As to the binding energy of different atomic nuclei, it turns out that
A. excepting radioactive elements, the most stable elements have mass numbers
of 100 or higher.
B. as binding energies increase, the stability of nuclei decreases.
C. binding energies are strongest among the light elements with the exception
of hydrogen.
D. the most stable elements have mass numbers of around 56.
(D?)

Which of the following is associated with β+ decay?
A. The parent and daughter nuclei still have the same n/p ratio.
B. The ratio of neutrons to protons is too low for stability.
C. Repulsion forces among large numbers of protons make the nucleus unstable.
D. The ratio of neutrons to protons is too high for stability.
(almost positive it is B)

All of the following statements are true except that
A. the amount of radioactive carbon in your body increases at the time of death.
B. radioactive carbon forms as atmospheric nitrogen is bombarded by high-energy
neutrons from outer space.
C. the amount of radioactive carbon in the air remains roughly constant over time.
D. radioactive carbon is absorbed by living things in the form of carbon dioxide.
(A?)

As to naming organic compounds, which statement is false?
A. The name 2,3-dimethylpentane tell you there are two or three alkyl groups in
the compound.
B. The first thing you do in naming an organic compound is count the number of carbon
atoms in a continuous chain.
C. Carbon groups that aren’t part of the main carbon chain are called side chains.
D. The name 2,3-dimethylpentane tells the location of methyl groups on the main
carbon chain.
(I think A)

Answer 1

I answered the above question first and did all of them although I thought some were poor questions and several had poor choices for answers. This set of question is even worse and I will leave them, although the last one should be D and the one before that I agree is A. Also I agree that the most stable elements are about Z = 56.