Rigid skeletons are formed from materials including chitin (in arthropods), calcium compounds such as calcium carbonate (in stony corals and mollusks) and silicate (for diatoms and radiolarians).
The answer is endoplasmatic reticulum.
Endoplasmatic reticulum forms a network of flatten tubules in the eukaryotic cells. It is involved in a synthesis of proteins and lipids. It enables transportation of proteins to the Golgi apparatus. Since enables transportation, a purpose of the endoplasmatic reticulum in the cell can be compared to a purpose of the roads in the town.
The correct answer is B. Gene Flow because gene flow is the mechanism of a change in the gene composition in a population as a result of migration. PLEASE MARK ME THE BRAINIEST.
