Small population size is your answer mate.
Binary fission occurs in single-celled organisms only and mitosis is just one cell dividing into two (eukaroytic cells)
Answer:
The nucleus contains the cell 's DNA and directs the synthesis of ribosomes and proteins. ... Ribosomes are large complexes of protein and ribonucleic acid responsible for protein synthesis when DNA from the nucleus is transcribed.
Explanation:
A. They impede fish migration and spawning
Cell -> tissue -> organ -> organ system -> organism
