Well, one historical problem with large scale immigration in the United States was the notion that immigrants were taking American jobs. If you look back into the early 1900's, when New York had a large number of Western European immigrants coming into the city, many business owners would put up signs like, "Help Wanted - Italians Need Not Apply", and this was interchangeable for any group business owners did not want applying for open jobs.
This claim is not entirely false though; the Center for Immigration Studies (CIS) has done research into immigration's effects on employment in the United States. By adding immigrants to the workforce, the U.S. GDP (gross domestic product) increases by $1.7-2 trillion a year. They have concluded that Americans hit by the brunt of this influx of immigrant workers are ones who are less-educated, most likely seeking blue-collar jobs, where immigrant workers would work for less than Americans.
Source: https://cis.org/Testimony/Impact-LargeScale-Immigration-American-Workers
Furthermore, if you are discussing illegal immigration, a massive issue is the literal disappearance of illegal immigrants once they enter the United States. As we can see from border issues today, the infrastructure cannot handle the sheer numbers of immigrants coming in, and once immigrants are caught, registered, and released into the country, it is very difficult to track them moving forward. This also encourages human trafficking over soft borders; it is estimated that drug cartels make over $150+ billion a year trafficking women and children over the U.S.-Mexico border.
Of these options, the only one that was truly true of both the first and second industrial revolution is the "use of the assembly line" although the length of these lines varied.
Surely only a few of us know that many modern high-school-level concepts in mathematics first were developed in Africa, as was the first method of counting. More than 35,000 years ago, Egyptians scripted textbooks about math that included division and multiplication of fractions and geometric formulas to calculate the area and volume of shapes (3). Distances and angles were calculated, algebraic equations were solved and mathematically based predictions were made of the size of floods of the Nile. The ancient Egyptians considered a circle to have 360 degrees and estimated Π at 3.16 (3).
Eight thousand years ago, people in present-day Zaire developed their own numeration system, as did Yoruba people in what is now Nigeria. The Yoruba system was based on units of 20 (instead of 10) and required an impressive amount of subtraction to identify different numbers. Scholars have lauded this system, as it required much abstract reasoning (4).
Astronomy
Several ancient African cultures birthed discoveries in astronomy. Many of these are foundations on which we still rely, and some were so advanced that their mode of discovery still cannot be understood. Egyptians charted the movement of the sun and constellations and the cycles of the moon. They divided the year into 12 parts and developed a yearlong calendar system containing 365 ¼ days (3). Clocks were made with moving water and sundial-like clocks were used (3).
A structure known as the African Stonehenge in present-day Kenya (constructed around 300 B.C.) was a remarkably accurate calendar (5). The Dogon people of Mali amassed a wealth of detailed astronomical observations (6). Many of their discoveries were so advanced that some modern scholars credit their discoveries instead to space aliens or unknown European travelers, even though the Dogon culture is steeped in ceremonial tradition centered on several space events. The Dogon knew of Saturn’s rings, Jupiter’s moons, the spiral structure of the Milky Way and the orbit of the Sirius star system. Hundreds of years ago, they plotted orbits in this system accurately through the year 1990 (6). They knew this system contained a primary star and a secondary star (now called Sirius B) of immense density and not visible to the naked eye.
Metallurgy and tools
Many advances in metallurgy and tool making were made across the entirety of ancient Africa. These include steam engines, metal chisels and saws, copper and iron tools and weapons, nails, glue, carbon steel and bronze weapons and art (2, 7).
Advances in Tanzania, Rwanda and Uganda between 1,500 and 2,000 years ago surpassed those of Europeans then and were astonishing to Europeans when they learned of them. Ancient Tanzanian furnaces could reach 1,800°C — 200 to 400°C warmer than those of the Romans (8).
Western Culture...................................
