Before, trains, cars, airplanes and trucks existed, rivers were used for travel. They carried people and goods. However, this way of transportation was very slow. All that changed with the arrival of the steamboat in the late 1700s and early 1800s. The steamboat could travel at the amazing speed of 5 miles per hour. It soon changed all over river travel and trade and dominated the waterways.
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.
<span>A major contribution was the establishment of hospitals, the educating of physicians was well structured, and physicians were meticulous with their record keeping to spread knowledge. Al Razi's great achievement was understanding the nature of illness. He also understood how the brain and nervous system operated muscles.</span>
I Believe The Answer Is Civilizations (B)
Hope This Helps!
I think d but I’m not sure
