What did the common ancestor of all modern tetra pods look like

Which type of scientific statement is defined as a hypothesis or group of hypotheses that can be accepted as true based on the repeated experimentation with similar results

Which type of respiration takes place when there is no oxygen present? a. anaerobic b. mitochondrial c. cellular d. aerobica. anaerobic

Which of the following is caused by reproductive isolation within a species? a. a decrease in gene flow b. an increase in genetic flow c. a decrease in genetic drift d. an increase in gene flow