According to scientists, how did early people migrate out of africa and into new places?
a. they used the wheel.
c. they used ships.
b. they used land bridges.
d. they used technology.

it is B. They used land bridges. hope it helps your friend Ω

the doctrine of nullification recommended that states living inside the union have the one-sided, inalienable ideal to void any law made by the national government that could be esteemed illegal.

the united states was shaped based on a general agreement among its individual states. hence, it is inferred that under the hypothesis of invalidation, since the states are the establishment of the union, they have the ability to referee and disprove unlawful laws.

a social contract.

"a social contract is an agreement between citizens and their leader where the citizens give up certain freedoms in exchange for protection. the constitution of the united states is an example of a social contract."