A theory in science is a remark on what happened
Bioaccumulation is the process by which chemicals are stored in the tissues of living organisms. It is the accumulation of chemicals in the tissue of organisms through any route including, respiration, ingestion or direct contact with contaminated water, sediment and pore water in the sediment. These chemical substances include, pesticides or other chemicals.
Two features that Eukaryotic cells have and prokaryotic cells lack:
1) Nucleus
2) Nuclear bound organelles like chloroplasts, Mitochondria, Golgi appratus etc
Hope this helps!
Any change or random error in a DNA sequence is called a mutation.