What is the ph of common solutions?

What two fields of study provide the core information that is used to classify organisms?

Select the situation bellow that would produce a total displacement of zero. a. a trip to the moon and then to mars b. a horse galloping from one end of a field to another c. the criss-crossing path of a bug as it flies from flower to flower d.a round-trip ride to school and back

Why are human population trends difficult to predict?