They are called bellwether species, also known as sentinel species.
Answer:
Demographic transition is the Topic
Explanation: Birth rate, death rate as regards to countries are being discussed but the information is not complete for proper assessment.
1 3 4. 5 6 are the ones that apply
Answer:
Validity or soundness of argument
Explanation:
An argument is said to be valid if it follows rightly from the premise and the premise is considered to be true making the conclusion true. This is called a sound or valid argument. In logic, we do not however say that an argument is false or true as this could only be said about the statement. Therefore an argument can only be valid or invalid but not false or true.
