Answer:
Explanation:
Oxygen is of no use to them, so they release it into the air. So there's a simple explanation for the Great Oxidation Event. It was the cyanobacteria, pumping out unwanted oxygen, that transformed Earth's atmosphere.
1.push factor
2.industrialization
3.utban crowding
4.income gap
5.pull factors
Answer:
d little to medium
Explanation:
because it is extremely cold
The correct answer is letter B. Horizontal water movements. Upwelling is a phenomenon that involves the dense's motion because of the wind. It is cooler and makes the water rich in nutrients towards the ocean surface. The warmer air is replaced and nutrient-depleted surface water are also replaced. This makes increase in plankton population and increase in nutrients at the ocean surface. The movement of the water is vertically up.
Answer:
sorry if its too big.
Explanation:
U.S. immigration has occurred in waves, with peaks followed by troughs (see figure). The first wave of immigrants, mostly English-speakers from the British Isles, arrived before records were kept beginning in 1820. The second wave, dominated by Irish and German Catholics in the 1840s and 1850s, challenged the dominance of the Protestant church and led to a backlash against Catholics, defused only when the Civil War practically stopped immigration in the 1860s.
The third wave, between 1880 and 1914, brought over 20 million European immigrants to the United States, an average of 650,000 a year at a time when the United States had 75 million residents. Most southern and eastern European immigrants arriving via New York’s Ellis Island found factory jobs in Northeastern and Midwestern cities. Third-wave European immigration was slowed first by World War I and then by numerical quotas in the 1920s.
Between the 1920s and 1960s, immigration paused. Immigration was low during the Depression of the 1930s, and in some years more people left the United States than arrived. Immigration rose after World War II ended, as veterans returned with European spouses and Europeans migrated. The fourth wave began after 1965, and has been marked by rising numbers of immigrants from Latin America and Asia. The United States admitted an average 250,000 immigrants a year in the 1950s, 330,000 in the 1960s, 450,000 in the 1970s, 735,000 in the 1980s, and over 1 million a year since the 1990s.
