They studied fossils (paleontology) and applied the principle that old layers or rock are lying just below young layers
The Clean Air Act was the major legislation passed to control air pollution in the United States.
The correct answer is the mainland Southeast Asia, The mainland Southeast Asia is the region called "the land of great lakes." That is because the mainland has many amazingly beautiful lakes surrounding the country, besides, not just lakes but also rivers and oceans.
Generally the biggest problems researchers encounter when conducting research in developing countries are related to ethical issues. There is often conflict between the ethical and moral standards of a given society and the researchers who will carry out the research, which makes it difficult and ambiguous to explain the cause of research without bumping into the dilemmas and cultural values of some community. However, some strategies may be used to ensure greater reliability and acceptability of research in some countries, some professional laws and codes may be used to attest to the protection of human dignity and to prevent scientific abuse. Historically, abuses and lack of professional ethics led to the creation of several codes of ethics. The Nuremberg Code, created in 1947 in order to protect human dignity in a research, guaranteeing the right to voluntary participation in a research can be cited as an example. as against physical and moral abuse.
The romans were the first one to come up with the idea.
