1. It has a living, flexible and thin structure. It possesses fine pores, making it semi-permeable. It is chiefly composed of lipo-proteins.   Hint Hint       2. It has a double-walled structure. Its inner wall is produced into folds known as cristae. It is generally sausage-shaped.   First letter clue   3. It is the largest cell organelle. It has a dense structure. It is spherical in shape.   Hint       4. It is chiefly composed of a dense fluid. It contains chromatin fibres, which are made up of DNA (Deoxyribonucleic acid).   First letter clue   5. It has numerous pores, making it semi-permeable. It is the covering of the nucleus of the cell.   First letter clue   6. It contains one or two centrioles, and is surrounded by microtubules or the centrosphere. It is situated near the nucleus.   First letter clue   7. It has a small, dense and granular structure. It is spherical in shape and is single-walled.   Hint