Well this is a very opinionated question but personally:
Astronauts improve society by using the newest and most expensive technology to be able to explore space as we know it.
Answer: Irrigation and terraces are still used today.
Answer:
Rail road companies facilitated settlement of the Great Plains because it provided a means of transportation for settlers to get to the location. The government had also provided land to these companies which they sold at an affordable cost to the new settlers. The area was a large expanse of flat land making it easy for newcomers to establish agriculture.
Answer:
This theory is true.
Explanation:
Whenever a nerve cell is stimulated, it emits a signal that will always cause the same sensation. Nerve cells are part of the nervous tissue of some organs and can be divided into two types: neurons and glial cells.
What you need to know about these cells, to consider the theory shown above to be true, is that nerve cells obey the "all or nothing" law, that is, no matter the intensity of the stimulus, if they are stimulated, the as little as possible, will always cause the same sensation.
