D. Carbohydrates are made of many sugars.
During transcription, the enzyme RNA polymerase (green) uses DNA as a template to produce a pre-mRNA transcript (pink). The pre-mRNA is processed to form a mature mRNA molecule that can be translated to build the protein molecule (polypeptide) encoded by the original gene.
Ventilation systems are needed in a <span>multicellular organism to actually obtain oxygen and give out carbon dioxide. Without this ventilation system, it would be very difficult for multicellular organisms to survive. It has been also observed that surface diffusion is not enough for a multicellular organism to breath.</span>
Cloning human cells, and growing bacon.
Multicellular organisms grow by producing more cells. As children, we get taller every year. That growth happens only because our bodies keep adding new cells. A sapling becomes a tree for the same reason.
But even after an organism grows up, its cells continue to divide. That's because cells wear out or get damaged.
Read more: Life Cycle of a Cell - Replacing Cells, Cell Division, Growth and Repair:, Mitosis, Specialized Sex Cells, Meiosis, Plant Sex Cells
