To date a sedimentary rock layer between two igneous rock units, geologists use radiometric dating and assume that the sedimentary layer’s age
is above that of the oldest of the two igneous units
is below that of the younger of the two igneous units
is between the absolute ages of the two igneous units

there's multiple reasons why the conquistadors were so successful in colonizing central america, and some of them are:

- they were seen as gods;

at the beginning, the spanish settlers were seen by the natives as gods, and this was mainly due to their white skin, and the way they came with their boats.

- possessed superior weaponry;

the spanish had gunpowder and guns, as well as cannons, while the natives did not had any fire weapons.

- made cleaver alliances;

they used the situation of tribes hating each other, so they made alliances with some of them which served them very well.

- brought diseases;

the native people were not immune to certain diseases the europeans brought with them, so they were dying from seeming harmless things for european standards.

b. 20: 5

explanation:

20% of the worlds population lives in southwest asia, and less than 5% of the world's

land area.