1. Rakib and Shahin have done research on micro- organisms. The subject of Rakib's research is on non- cellular pathogenic micro-organisms and Shahin's is on prokaryotic micro-organisms. Rakib's observation showed that the replication of his micro-organisms increased by eating the micro-organisms of Shahin.
4. The 'A' organelle of living cell is called the protcin factory and the ' ' organelle is called the traffic police of cell.