Answer:
Researchers initially built up the geologic time scale by considering rock layers and record fossils around the world. With this data, researchers put in Earth's stone layers in request by relative age. Afterward, radioactive dating decided the supreme age of the divisions in the geologic time scale.
Answer:
D. A silent variant near the 5' end of the TBX1 gene.
Explanation:
TBX1 gene is wild type human being. It gives instructions for making protein called T-box 1. It plays an important role in tissue formation and organs during embryonic development.