Question

1. the primary fasteners on your robots are these. they are usually attached using a threaded nut.

a. nut
b. wrench
c. allen key
d. screw/bolt
e. rivet

Explanation:

The description mentions primary fasteners attached with a threaded nut. A screw - bolt is a fastener that is typically used with a nut. A nut is just the part that is threaded and used with a bolt, a wrench is a tool for tightening/loosening nuts and bolts, an allen key is for allen - head screws, and a rivet is a different type of fastener that is not used with a nut.

Answer:

D. screw - bolt