Vestigial structures, homologous structures, and biochemical similarities all provide evidence of:a. descent from a common ancestorb. barriers to migrationc. random matingd. sexual selection

Step by Step Solution: Step 1. The first step to answering this question is to understand what each of the given terms means. Step 2. Vestigial structures are structures that have lost their function in the course of evolution, but their remnants are still present in the organism. Step 3. Homologous structures are structures in different organisms that share a similar structure and developmental origin, but may have different functions. Step 4. Biochemical similarities refer to similarities in the molecular composition or genetic makeup of different organisms. Step 5. Putting this information together, we can conclude that vestigial structures, homologous structures, and biochemical similarities provide evidence of descent from a common ancestor, which is option (a). Final Answer: a. descent from a common ancestor