Which of the following triggered the second industrial revolution?

a. geologists discovered vast quantities of petroleum in germany
b. entrepreneurs figured out how to extract coal much more efficiently
c. innovators figured out how to produce steel cheaply
d. engineers developed a much faster steam engine

I think its:

C. Innovators figured out how to produce steel cheaply

the supreme court can hear any case it wishes as long as four justices agree to hear it.

hope this , give me brainliest answer =j

answer: andrew johnson

17th u.s. president

in what way were president abraham lincoln's and president andrew johnson's reconstruction plans similar? a)both reserved seats in the congress for former confederate war leaders. b)both granted voting rights to the newly freed slaves. d) both required southerners to support the thirteenth amendment to abolish

explanation: