Genetic variation is when there are many offspring with different genetics, therefore some offspring might be able to adapt due to its genetics
You can reduce the risks of radiation exposure by:
1. Eating foods that contain chlorophyll. Foods that contain this substance detoxify the blood, helping to remove all kinds of nasty toxins including radiation.
2. Ingest sea vegetables. Kelp, dulse, and agar contain natural iodine, which protects against radioactive iodine found in foods like dairy products.
3. Supplement with bee pollen. It can protect your body against x-ray induced radiation sickness.
4. Limit daily exposure to nonionizing radiation.
A difference between coelom and Pseudocoelom is that the gut of a pseudocoelom is surrounded by the endoderm, and the gut of a coelomate is surrounded by the ectoderm. So your answer is D.