3. They invaded countries to create empires.
Answer:
HIV is a virus that attack the cell which helps to fight against infection and make person suffer from others infections and diseases.
Aquired immunodeficiency syndrome is the Aids caused by HIV virus that is chronic.
If the natural quality of water is destroyed by mixing unwanted and harmful substances in water, it is called water pollution.
The rate of production of new biomass by an individual, population, or community; the fertility or capacity of a given habitat or area.
It was the most powerful civilization
