What military advantage did the Qin have over the other northern states in battle? horse-drawn chariots
body armor
an extensive navy
iron weapons

iron weapons

Explanation:

During the Qin dynasty, the iron weapon became widespread in their military and this had an impact on their military strength.

The iron industry was in high use during this dynasty, and many metal products were generally used (tools, weapons, dishes, etc.)

Archeologists found various iron weapons from this time, such as swords, spears, saggers, machete, as well as various shooting weapons.

in what process is there a multiple choice answer?

d is the correct answer.

b is incorrect because it makes food by itself

c is incorrect because us humans don't know how to produce their own food using the sun like plants.

a is incorrect because consumers can depend on carnivores for eating food for consumers to eat the dead organism. same thing with omnivores.