If you are conducting a study on the health of people who have been exposed vs not exposed, the method you should use to obtain data would be an observational study because it involves the pre-existing condition of the subjects.
Answer:
Tertiary consumer,secondary consumer, primary consumer, producers
Explanation:
produces : Plants which make their own food and are called producers.
primary consumer: Herbivores eat plants and are called primary consumers.
secondary consumer: Carnivores that eat herbivores are called secondary consumers .
tertiary consumer: Carnivores that eat other carnivores are called tertiary consumers
Russia's population density is 8.4 people per square kilometre (22 per square mile), making it one of the most sparsely populated countries in the world.
