The answer to this question is:
A. Barley and wheat were both civilizations' main crops
Happy Studying!!! :)
Caldera is a very large it depression at the top of some volcanoes do.
Hope it helped you.
-Charlie
Answer:
D. troposphere; stratosphere
Explanation:
The ozone layer is a region in the upper part of the earth that is rich in ozone content (three molecules of oxygen or trioxygen O3). This layers extends as a blanket over the earth's globe as it absorbs the dangerous ultraviolet radiation from the sun preventing it from reaching the earth surface.
Ozone is a potential air pollutant when found in the ground level of the earth, the troposphere. It causes greenhouse gases, contributes to climate change and global warming threatening the health of living things at this region. However, Ozone is useful in the stratosphere where it helps in trapping incoming radiation from the Sun that would have been harmful to life on the earth.
C. controlled population growth
Controlled population growth has had virtually no effect on farming and is an ideology for the population which is scarcely used in the United States. However, expansive infrastructure and mechanized equipment has kick started mass production of produce, while access to expensive chemical fertilizers and pesticides has helped the United States to grow more quicker and for produce to last longer. The prohibition of hybridized crops has led to a healthier way of farming, such as organic farming which has proved successful and popular in the United States.
Because they get the warmer air from the oceans