Option D centrioles helps cells to divide.
The cell is made up of different organelles, which work together in order to ensure that the biochemical activities, which keep the cell alive run smoothly. Lets take the eukaryotic cell for example: the cell is made up of many organelles and each organelle has a particular function that it carries out, this function complements the functions of other cell organelles.
For instance, for protein synthesis to occur, many organelles has to work together, these include: nucleus, DNA, ribosomes, cytoplasm, smooth endoplasmic reticulum, rough endoplasmic reticulum, golgi apparatus, etc. If the ribosomes is not functioning perfectly, the protein synthesis can not be completed, thus, all cell's organelle working together on a specific process must function optimally individually and work together as a team in order to execute the process.
The two membranes pull apart a little and create a small pocket or sack of air. As the developing bird grows, it breathes in oxygen from the air sack and exhales carbon dioxide. Several thousand microscopic pores all over the surface of the egg allow the CO2 to escape and fresh air to get in.
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