Question

which invention by carl siemens helped make the second industrial revolution possible?
o an expanded system of telephones
o a way to make large quantities of steel in a gas furnace
o insulation for telegraph wires
o an internal combustion engine

Explanation:

Carl Siemens developed a process to produce large - scale steel in a gas furnace, which was crucial for the Second Industrial Revolution as steel was a key material for construction, machinery, etc. The other options are not his main inventions related to the Second Industrial Revolution's key advancements.

Answer:

a way to make large quantities of steel in a gas furnace