Answer:
Option: A. True
Explanation:
The Maya civilization covers regions that spread from northern Mexico southwards into Central America. The Maya stretched from modern-day southern Mexico through Guatemala, Honduras, and Belize. The culture is renowned for its massive pyramids, irrigation systems and agriculture, and symbols. Most of the ruins are still discover in the jungles of Mexico and Guatemala, which remain unknown since the colonial period in Mexico under the Spanish Empire. The civilization fizzled out between A.D. 800 and 1000 before the arrival of Spanish in Central America that led structures remain untouched in the jungle for centuries.
The answer to your question is A
Two statements support the claim that Jenner has been given credit for starting and spreading the practice of immunization:
- Jenner became interested in the protective effects of cowpox during his apprenticeship. Here, we are told that Edward Jenner started working on ways to defend the body against diseases as early as during his apprenticeship when he was a teenager. He had been told that farm workers who had contracted cowpox were immune to the smallpox epidemic which was spreading across Europe at the time. He then started working on a vaccine containing cowpox.
- Jenner made the first step to erase smallpox. This first step was to try his new smallpox vaccine on a child in 1796. The child did not catch smallpox. In order to get recognition and validation from the authorities, Jenner administered his vaccine to 22 more people, with success.
Answer:
Scientists use waves to study the different layers of the earth. Usually, they use seismic waves, which are waves generated by earthquakes or nuclear-test explosions. The seismic waves are bent, sped up, or slowed down, or even reflected when they pass through the earth's layers.
Seismic waves are recorded by a machine called a seismograph, which tells us about the strength and speed of the seismic waves. ... Seismic waves travel at different speeds when they pass through different types of material, so by studying seismograms, scientists can learn a lot about Earth's internal structure.
Explanation:
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