Lead is cheap and does not corrode like other metals in the presence of battery acid. It is also soft enough to conform tightly around the battery post and conducts electricity very well.
The actual bolts and nuts themselves are not lead, being too soft a material for the torque needed to secure the cable connector terminals to the battery's posts.
The negative battery lead cable is to be connected to the negative lead terminal on the battery.
Follow the positive battery cable from the battery, it will lead you right to the starter.
Follow the positive battery cable from the battery, it will lead you right to the starter.
Follow the positive battery cable from the battery, it will lead you to the starter.
Follow the positive battery cable and it will lead to it.
Follow the positive battery cable from the battery, it will lead you right to the starter.
Follow the positive battery cable from the battery, it will lead you right to the starter.
It is mounted on top of the starter, to the starter. Follow the positive battery cable from the battery, it will lead you right to it.
Follow the positive battery cable from the battery, it will lead you right to the starter.
Follow the positive battery cable from the battery. It will lead you to the starter.
Passenger side, bottom of engine, just follow the positive battery cable from the battery, it will lead you right to it.
You didn't say what engine you have but, if you follow the positive battery cable from the battery it will lead you to the starter.