Answer:
Chromosomes
Explanation:
Multicellular organism are organisms that have more than one cells in their body. However, from the very beginning of every living organism including multicellular organisms, only ONE cell is required. In the case of multicellular organisms, this one cell undergoes division by mitosis to form other cells.
Since the cells divide by mitosis i.e 1 forms 2, 2 forms 4 etc.,. each of the cells are genetically identical to one another. Hence, this means that all the cells will contain the same number of chromosomes in their genome. For example, a dog as a multicellular organism has cells that emanate from one cell. If that one cell contain 39 chromosomes, all cells in the dog will also contain 39 chromosomes.
When the organism become bipedal, they walk with 2 legs so there are 2 arms that were unused. Some of them try to use that hand by grabbing stick or stone, leading to tools. They start to think more to develop tools and their brain capacity become increased.
The ability to use stone tools will help in food digestion since it can break the food easier. This reduces the needs for bigger teeth/jaw.
Answer:
Replication only happens before mitosis and meiosis because in this process the whole DNA is turned into two copies of it, in order for the cell to duplicate. Otherwise, the transcription, which is the first step for protein synthesis, happens all the time in the cell and only works in specific genes that codify for specific proteins. If the DNA was replicated every time a protein is needed, the cell would have millions of DNA copies for no purpose at all, meaning a big waste of energy and space.
The Electron Transport Chain