The polar coordinate model assigns positional values to cells in polar coordinates. Intercalary regenerates are always derived from more distal cells. The shortest intercalation rule states that the short axis of a rectangular field is restored before the long axis. The polar coordinate model is based on two morphogens. Complete each of the following sentences by inserting one word into each blank space so that a scientifically and linguistically correct statement results.
Hyphenated words count as one word.
Many molluscs are characterized by the occurrence of a polar lobe during the first two cleavages. A. Diagram the fate of the polare lobe during the first two cleavages. C. Describe experimental evidence for the proposed function. A. Define the morphogenetic movement of involution in general terms. B. Describe experimental results showing that involution occurs during amphibian gastrulation.