According to the bering land bridge theory, how do scientists think people first arrived in north america?
(a) after the ice age glaciers melted and people came in small boats.
(b) after the ice age glaciers melted and people crossed land
(c) during the ice age the sea level dropped and people crossed land
(d) during the ice age the sea froze and people crossed the ice
if able answer whole quiz

The correct answer is C. During the ice age the sea level dropped and people crossed land

Explanation:

The Bering Land Bridge Theory claims human groups firsts arrived from Asia to America by crossing Beringia which was a natural land bridge that formed around 16000 years ago as in this zone as due to the glaciation period the level of the sea reduced and a natural bridge land between the two continents emerged. According to this theory, it was this bridge land between Siberia and Alaska human groups use to migrate to America as well as different animal species that also crossed this bridge and then spread through all the continent. Thus, in the Bering Land Bridge Theory people arrive in North America as "during the ice age the sea level dropped and people crossed land".

marginal cost is a microeconomic measure that us to evaluate the extent to which the level of production of a good is sustainable in accounting, that is, to how many quantities the company plans to profit from the production of the good.

the concept of marginal cost is simple, it means the cost of producing one more item. for example, in the case of pies, the marginal cost is the cost of producing one more pie than those that have already been produced.

it is important to understand that productive activity influences marginal cost. the marginal cost of some goods can be very high, while others may be insignificant. for example, the marginal cost of producing an extra plane is very high. already the marginal cost of a water company to provide 1l more water is derisory.

in the case of pies, the cost involves the inputs, the labor and the fixed cost, which involves the fixed space of the bakery. the level of production initially has the marginal cost decreasing because there is space and manpower available. however, to produce more you have to hire more workers and buy more inputs. if physical space is limited, workers will conflict with places, inputs and their productivity will decrease, meaning there is an optimum point of production for each level of space and manpower. from this point on, the productivity of the workers will be getting smaller because of lack of space, so that the marginal cost of producing one more pie will be increasing. so, although you have not posted the chart, but if you have the answer, you can see that my explanation goes according to the marginal cost curve that will increase from the 4th pie, answer (c).