Final answer:
The basis for these statements is scientific data, opinions of experts, and sound principles of practice.
Step-by-step explanation:
The basis for these statements is scientific data, opinions of experts, and sound principles of practice. Scientific data is gathered through observation, experimentation, and measurement, providing empirical evidence to support or refute statements. Opinions of experts come from individuals who have extensive knowledge and experience in the field, and their opinions are valued due to their expertise. Sound principles of practice are established based on proven methods and best practices that are supported by scientific data and expert opinions.